diff --git a/command.py b/command.py
index 38cacd3..78dab96 100644
--- a/command.py
+++ b/command.py
@@ -106,13 +106,13 @@
   def _UpdatePathToProjectMap(self, project):
     self._by_path[project.worktree] = project
 
-  def _GetProjectByPath(self, path):
+  def _GetProjectByPath(self, manifest, path):
     project = None
     if os.path.exists(path):
       oldpath = None
       while path \
         and path != oldpath \
-        and path != self.manifest.topdir:
+        and path != manifest.topdir:
         try:
           project = self._by_path[path]
           break
@@ -126,13 +126,16 @@
         pass
     return project
 
-  def GetProjects(self, args, groups='', missing_ok=False, submodules_ok=False):
+  def GetProjects(self, args, manifest=None, groups='', missing_ok=False,
+                  submodules_ok=False):
     """A list of projects that match the arguments.
     """
-    all_projects_list = self.manifest.projects
+    if not manifest:
+      manifest = self.manifest
+    all_projects_list = manifest.projects
     result = []
 
-    mp = self.manifest.manifestProject
+    mp = manifest.manifestProject
 
     if not groups:
         groups = mp.config.GetString('manifest.groups')
@@ -155,11 +158,11 @@
       self._ResetPathToProjectMap(all_projects_list)
 
       for arg in args:
-        projects = self.manifest.GetProjectsWithName(arg)
+        projects = manifest.GetProjectsWithName(arg)
 
         if not projects:
           path = os.path.abspath(arg).replace('\\', '/')
-          project = self._GetProjectByPath(path)
+          project = self._GetProjectByPath(manifest, path)
 
           # If it's not a derived project, update path->project mapping and
           # search again, as arg might actually point to a derived subproject.
@@ -170,7 +173,7 @@
               self._UpdatePathToProjectMap(subproject)
               search_again = True
             if search_again:
-              project = self._GetProjectByPath(path) or project
+              project = self._GetProjectByPath(manifest, path) or project
 
           if project:
             projects = [project]
diff --git a/gitc_utils.py b/gitc_utils.py
index ef028b0..4d8d536 100644
--- a/gitc_utils.py
+++ b/gitc_utils.py
@@ -16,6 +16,7 @@
 from __future__ import print_function
 import os
 import sys
+import time
 
 import git_command
 import git_config
@@ -26,6 +27,18 @@
 GITC_FS_ROOT_DIR = '/gitc/manifest-rw/'
 NUM_BATCH_RETRIEVE_REVISIONID = 300
 
+def parse_clientdir(gitc_fs_path):
+  """Parse a path in the GITC FS and return its client name.
+
+  @param gitc_fs_path: A subdirectory path within the GITC_FS_ROOT_DIR.
+
+  @returns: The GITC client name
+  """
+  if (gitc_fs_path == GITC_FS_ROOT_DIR or
+      not gitc_fs_path.startswith(GITC_FS_ROOT_DIR)):
+    return None
+  return gitc_fs_path.split(GITC_FS_ROOT_DIR)[1].split('/')[0]
+
 def _set_project_revisions(projects):
   """Sets the revisionExpr for a list of projects.
 
@@ -50,19 +63,37 @@
       sys.exit(1)
     proj.revisionExpr = gitcmd.stdout.split('\t')[0]
 
-def generate_gitc_manifest(client_dir, manifest):
+def generate_gitc_manifest(client_dir, manifest, projects=None):
   """Generate a manifest for shafsd to use for this GITC client.
 
   @param client_dir: GITC client directory to install the .manifest file in.
   @param manifest: XmlManifest object representing the repo manifest.
+  @param projects: List of projects we want to update, this must be a sublist
+                   of manifest.projects to work properly. If not provided,
+                   manifest.projects is used.
   """
   print('Generating GITC Manifest by fetching revision SHAs for each '
         'project.')
+  if projects is None:
+    projects = manifest.projects
   index = 0
-  while index < len(manifest.projects):
+  while index < len(projects):
     _set_project_revisions(
-        manifest.projects[index:(index+NUM_BATCH_RETRIEVE_REVISIONID)])
+        projects[index:(index+NUM_BATCH_RETRIEVE_REVISIONID)])
     index += NUM_BATCH_RETRIEVE_REVISIONID
   # Save the manifest.
+  save_manifest(manifest, client_dir=client_dir)
+
+def save_manifest(manifest, client_dir=None):
+  """Save the manifest file in the client_dir.
+
+  @param client_dir: Client directory to save the manifest in.
+  @param manifest: Manifest object to save.
+  """
+  if not client_dir:
+    client_dir = manifest.gitc_client_dir
   with open(os.path.join(client_dir, '.manifest'), 'w') as f:
     manifest.Save(f)
+  # TODO(sbasi/jorg): Come up with a solution to remove the sleep below.
+  # Give the GITC filesystem time to register the manifest changes.
+  time.sleep(3)
\ No newline at end of file
diff --git a/main.py b/main.py
index 6736abc..adfaffb 100755
--- a/main.py
+++ b/main.py
@@ -51,7 +51,8 @@
 from error import NoManifestException
 from error import NoSuchProjectError
 from error import RepoChangedException
-from manifest_xml import XmlManifest
+import gitc_utils
+from manifest_xml import GitcManifest, XmlManifest
 from pager import RunPager
 from wrapper import WrapperPath, Wrapper
 
@@ -129,6 +130,12 @@
 
     cmd.repodir = self.repodir
     cmd.manifest = XmlManifest(cmd.repodir)
+    cmd.gitc_manifest = None
+    gitc_client_name = gitc_utils.parse_clientdir(os.getcwd())
+    if gitc_client_name:
+      cmd.gitc_manifest = GitcManifest(cmd.repodir, gitc_client_name)
+      cmd.manifest.isGitcClient = True
+
     Editor.globalConfig = cmd.manifest.globalConfig
 
     if not isinstance(cmd, MirrorSafeCommand) and cmd.manifest.IsMirror:
diff --git a/manifest_xml.py b/manifest_xml.py
index 6dc01a4..b33ec62 100644
--- a/manifest_xml.py
+++ b/manifest_xml.py
@@ -29,6 +29,7 @@
   urllib = imp.new_module('urllib')
   urllib.parse = urlparse
 
+import gitc_utils
 from git_config import GitConfig
 from git_refs import R_HEADS, HEAD
 from project import RemoteSpec, Project, MetaProject
@@ -112,6 +113,7 @@
     self.manifestFile = os.path.join(self.repodir, MANIFEST_FILE_NAME)
     self.globalConfig = GitConfig.ForUser()
     self.localManifestWarning = False
+    self.isGitcClient = False
 
     self.repoProject = MetaProject(self, 'repo',
       gitdir   = os.path.join(repodir, 'repo/.git'),
@@ -306,6 +308,8 @@
       if p.clone_depth:
         e.setAttribute('clone-depth', str(p.clone_depth))
 
+      self._output_manifest_project_extras(p, e)
+
       if p.subprojects:
         subprojects = set(subp.name for subp in p.subprojects)
         output_projects(p, e, list(sorted(subprojects)))
@@ -323,6 +327,10 @@
 
     doc.writexml(fd, '', '  ', '\n', 'UTF-8')
 
+  def _output_manifest_project_extras(self, p, e):
+    """Manifests can modify e if they support extra project attributes."""
+    pass
+
   @property
   def paths(self):
     self._Load()
@@ -712,7 +720,7 @@
   def _UnjoinName(self, parent_name, name):
     return os.path.relpath(name, parent_name)
 
-  def _ParseProject(self, node, parent = None):
+  def _ParseProject(self, node, parent = None, **extra_proj_attrs):
     """
     reads a <project> element from the manifest file
     """
@@ -807,7 +815,8 @@
                       clone_depth = clone_depth,
                       upstream = upstream,
                       parent = parent,
-                      dest_branch = dest_branch)
+                      dest_branch = dest_branch,
+                      **extra_proj_attrs)
 
     for n in node.childNodes:
       if n.nodeName == 'copyfile':
@@ -938,3 +947,26 @@
       diff['added'].append(toProjects[proj])
 
     return diff
+
+
+class GitcManifest(XmlManifest):
+
+  def __init__(self, repodir, gitc_client_name):
+    """Initialize the GitcManifest object."""
+    super(GitcManifest, self).__init__(repodir)
+    self.isGitcClient = True
+    self.gitc_client_name = gitc_client_name
+    self.gitc_client_dir = os.path.join(gitc_utils.GITC_MANIFEST_DIR,
+                                        gitc_client_name)
+    self.manifestFile = os.path.join(self.gitc_client_dir, '.manifest')
+
+  def _ParseProject(self, node, parent = None):
+    """Override _ParseProject and add support for GITC specific attributes."""
+    return super(GitcManifest, self)._ParseProject(
+        node, parent=parent, old_revision=node.getAttribute('old-revision'))
+
+  def _output_manifest_project_extras(self, p, e):
+    """Output GITC Specific Project attributes"""
+    if p.old_revision:
+        e.setAttribute('old-revision', str(p.old_revision))
+
diff --git a/project.py b/project.py
index a8d012d..f964b2f 100644
--- a/project.py
+++ b/project.py
@@ -572,7 +572,8 @@
                parent=None,
                is_derived=False,
                dest_branch=None,
-               optimized_fetch=False):
+               optimized_fetch=False,
+               old_revision=None):
     """Init a Project object.
 
     Args:
@@ -596,6 +597,7 @@
       dest_branch: The branch to which to push changes for review by default.
       optimized_fetch: If True, when a project is set to a sha1 revision, only
                        fetch from the remote if the sha1 is not present locally.
+      old_revision: saved git commit id for open GITC projects.
     """
     self.manifest = manifest
     self.name = name
@@ -643,6 +645,7 @@
     self.bare_ref = GitRefs(gitdir)
     self.bare_objdir = self._GitGetByExec(self, bare=True, gitdir=objdir)
     self.dest_branch = dest_branch
+    self.old_revision = old_revision
 
     # This will be filled in if a project is later identified to be the
     # project containing repo hooks.
@@ -1195,6 +1198,8 @@
     self._InitHooks()
 
   def _CopyAndLinkFiles(self):
+    if self.manifest.isGitcClient:
+      return
     for copyfile in self.copyfiles:
       copyfile._Copy()
     for linkfile in self.linkfiles:
@@ -1425,9 +1430,11 @@
 
 ## Branch Management ##
 
-  def StartBranch(self, name):
+  def StartBranch(self, name, branch_merge=''):
     """Create a new branch off the manifest's revision.
     """
+    if not branch_merge:
+      branch_merge = self.revisionExpr
     head = self.work_git.GetHead()
     if head == (R_HEADS + name):
       return True
@@ -1441,9 +1448,9 @@
 
     branch = self.GetBranch(name)
     branch.remote = self.GetRemote(self.remote.name)
-    branch.merge = self.revisionExpr
-    if not branch.merge.startswith('refs/') and not ID_RE.match(self.revisionExpr):
-      branch.merge = R_HEADS + self.revisionExpr
+    branch.merge = branch_merge
+    if not branch.merge.startswith('refs/') and not ID_RE.match(branch_merge):
+      branch.merge = R_HEADS + branch_merge
     revid = self.GetRevisionId(all_refs)
 
     if head.startswith(R_HEADS):
@@ -1451,7 +1458,6 @@
         head = all_refs[head]
       except KeyError:
         head = None
-
     if revid and head and revid == head:
       ref = os.path.join(self.gitdir, R_HEADS + name)
       try:
diff --git a/subcmds/start.py b/subcmds/start.py
index 60ad41e..188fd7c 100644
--- a/subcmds/start.py
+++ b/subcmds/start.py
@@ -14,11 +14,15 @@
 # limitations under the License.
 
 from __future__ import print_function
+import os
 import sys
+
 from command import Command
 from git_config import IsId
 from git_command import git
+import gitc_utils
 from progress import Progress
+from project import SyncBuffer
 
 class Start(Command):
   common = True
@@ -53,20 +57,50 @@
         print("error: at least one project must be specified", file=sys.stderr)
         sys.exit(1)
 
-    all_projects = self.GetProjects(projects)
+    proj_name_to_gitc_proj_dict = {}
+    if self.gitc_manifest:
+      all_projects = self.GetProjects(projects, manifest=self.gitc_manifest,
+                                      missing_ok=True)
+      for project in all_projects:
+        if project.old_revision:
+          project.already_synced = True
+        else:
+          project.already_synced = False
+          project.old_revision = project.revisionExpr
+        proj_name_to_gitc_proj_dict[project.name] = project
+        project.revisionExpr = None
+      # Save the GITC manifest.
+      gitc_utils.save_manifest(self.gitc_manifest)
 
+    all_projects = self.GetProjects(projects,
+                                    missing_ok=bool(self.gitc_manifest))
     pm = Progress('Starting %s' % nb, len(all_projects))
     for project in all_projects:
       pm.update()
+      if self.gitc_manifest:
+        gitc_project = proj_name_to_gitc_proj_dict[project.name]
+        # Sync projects that have already been opened.
+        if not gitc_project.already_synced:
+          proj_localdir = os.path.join(self.gitc_manifest.gitc_client_dir,
+                                       project.relpath)
+          project.worktree = proj_localdir
+          if not os.path.exists(proj_localdir):
+            os.makedirs(proj_localdir)
+          project.Sync_NetworkHalf()
+          sync_buf = SyncBuffer(self.manifest.manifestProject.config)
+          project.Sync_LocalHalf(sync_buf)
+          project.revisionExpr = gitc_project.old_revision
+
       # If the current revision is a specific SHA1 then we can't push back
       # to it; so substitute with dest_branch if defined, or with manifest
       # default revision instead.
+      branch_merge = ''
       if IsId(project.revisionExpr):
         if project.dest_branch:
-          project.revisionExpr = project.dest_branch
+          branch_merge = project.dest_branch
         else:
-          project.revisionExpr = self.manifest.default.revisionExpr
-      if not project.StartBranch(nb):
+          branch_merge = self.manifest.default.revisionExpr
+      if not project.StartBranch(nb, branch_merge=branch_merge):
         err.append(project)
     pm.end()
 
diff --git a/subcmds/sync.py b/subcmds/sync.py
index ad0ecdf..934aaa8 100644
--- a/subcmds/sync.py
+++ b/subcmds/sync.py
@@ -549,15 +549,6 @@
              cwd.split(gitc_utils.GITC_MANIFEST_DIR)[1]))
       sys.exit(1)
 
-    self._gitc_sync = False
-    if cwd.startswith(gitc_utils.GITC_FS_ROOT_DIR):
-      self._gitc_sync = True
-      self._client_name = cwd.split(gitc_utils.GITC_FS_ROOT_DIR)[1].split(
-          '/')[0]
-      self._client_dir = os.path.join(gitc_utils.GITC_MANIFEST_DIR,
-                                      self._client_name)
-      print('Updating GITC client: %s' % self._client_name)
-
     if opt.manifest_name:
       self.manifest.Override(opt.manifest_name)
 
@@ -677,12 +668,6 @@
     if opt.repo_upgraded:
       _PostRepoUpgrade(self.manifest, quiet=opt.quiet)
 
-    if self._gitc_sync:
-      gitc_utils.generate_gitc_manifest(self._client_dir, self.manifest)
-      print('GITC client successfully synced.')
-      return
-
-
     if not opt.local_only:
       mp.Sync_NetworkHalf(quiet=opt.quiet,
                           current_branch_only=opt.current_branch_only,
@@ -697,6 +682,35 @@
       self._ReloadManifest(manifest_name)
       if opt.jobs is None:
         self.jobs = self.manifest.default.sync_j
+
+    # TODO (sbasi) - Add support for manifest changes, aka projects
+    # have been added or deleted from the manifest.
+    if self.gitc_manifest:
+      gitc_manifest_projects = self.GetProjects(args,
+                                                manifest=self.gitc_manifest,
+                                                missing_ok=True)
+      gitc_projects = []
+      opened_projects = []
+      for project in gitc_manifest_projects:
+        if not project.old_revision:
+          gitc_projects.append(project)
+        else:
+          opened_projects.append(project)
+
+      if gitc_projects and not opt.local_only:
+        print('Updating GITC client: %s' % self.gitc_manifest.gitc_client_name)
+        gitc_utils.generate_gitc_manifest(self.gitc_manifest.gitc_client_dir,
+                                          self.gitc_manifest,
+                                          gitc_projects)
+        print('GITC client successfully synced.')
+
+      # The opened projects need to be synced as normal, therefore we
+      # generate a new args list to represent the opened projects.
+      args = []
+      for proj in opened_projects:
+        args.append(os.path.relpath(proj.worktree, cwd))
+      if not args:
+        return
     all_projects = self.GetProjects(args,
                                     missing_ok=True,
                                     submodules_ok=opt.fetch_submodules)