diff --git a/src/s1ap/handlers/attach_reject.c b/src/s1ap/handlers/attach_reject.c
new file mode 100644
index 0000000..38c20dd
--- /dev/null
+++ b/src/s1ap/handlers/attach_reject.c
@@ -0,0 +1,231 @@
+/*
+* Copyright 2019-present Open Networking Foundation
+*
+* SPDX-License-Identifier: Apache-2.0
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+*  http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*
+*/
+#include <stdio.h>
+#include <stdlib.h>
+#include <pthread.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "log.h"
+#include "err_codes.h"
+#include "s1ap.h"
+#include "message_queues.h"
+#include "ipc_api.h"
+#include "main.h"
+#include "sctp_conn.h"
+#include "msgType.h"
+
+
+
+
+/**
+* Get ProtocolIE value for Auth Request sent by mme-app
+*/
+static int
+get_attachReject_protoie_value(struct proto_IE *value, struct attachReqRej_info *g_attachReqRejInfo)
+{
+	value->no_of_IEs = AUTH_REQ_NO_OF_IES;
+
+	value->data = (proto_IEs *) malloc(ATTACH_REJECT_NO_OF_IES*
+			sizeof(proto_IEs));
+
+	value->data[0].val.mme_ue_s1ap_id = g_attachReqRejInfo->ue_idx;
+	value->data[1].val.enb_ue_s1ap_id = g_attachReqRejInfo->s1ap_enb_ue_id;
+
+	log_msg(LOG_INFO, "mme_ue_s1ap_id %d and enb_ue_s1ap_id %d\n",
+			g_attachReqRejInfo->ue_idx, g_attachReqRejInfo->s1ap_enb_ue_id);
+
+	/* TODO: Add enum for security header type */
+	value->data[2].val.nas.header.security_header_type = 0;
+	value->data[2].val.nas.header.proto_discriminator = EPSMobilityManagementMessages;
+	value->data[2].val.nas.header.message_type = AttachReject;
+	value->data[2].val.nas.header.nas_security_param = 0;
+
+#if 0
+	value->data[2].nas.elements = (nas_pdu_elements *)
+			malloc(AUTH_REQ_NO_OF_NAS_IES * sizeof(nas_pdu_elements));
+
+	memcpy(value->data[2].nas.elements[0].rand,
+			g_attachReqRejInfo->rand, NAS_RAND_SIZE);
+	memcpy(value->data[2].nas.elements[1].autn,
+			g_attachReqRejInfo->autn, NAS_AUTN_SIZE);
+#endif
+
+
+	return SUCCESS;
+}
+
+
+/**
+* Stage specific message processing.
+*/
+static int
+s1ap_attach_reject_processing(struct attachReqRej_info *g_attachReqRejInfo)
+{
+	struct Buffer g_buffer;
+	struct Buffer g_value_buffer;
+	struct Buffer g_nas_buffer;
+	struct s1ap_PDU s1apPDU= {0};
+
+
+
+	/* Assigning values to s1apPDU */
+	s1apPDU.procedurecode = id_downlinkNASTransport;
+	s1apPDU.criticality = CRITICALITY_IGNORE;
+
+	get_attachReject_protoie_value(&s1apPDU.value,g_attachReqRejInfo);
+
+	/* Copy values to buffer from s1apPDU */
+
+	g_buffer.pos = 0;
+
+	uint8_t initiating_message = 0; /* TODO: Add enum */
+	buffer_copy(&g_buffer, &initiating_message,
+			sizeof(initiating_message));
+
+	buffer_copy(&g_buffer, &s1apPDU.procedurecode,
+			sizeof(s1apPDU.procedurecode));
+
+	buffer_copy(&g_buffer, &s1apPDU.criticality,
+			sizeof(s1apPDU.criticality));
+
+	/* Copy values in g_value_buffer */
+	g_value_buffer.pos = 0;
+
+	/* TODO remove hardcoded values */
+	unsigned char chProtoIENo[3] = {0,0,3};
+
+	buffer_copy(&g_value_buffer, chProtoIENo, 3);
+
+	unsigned char tmpStr[4];
+
+	/* id-MME-UE-S1AP-ID */
+	uint16_t protocolIe_Id = id_MME_UE_S1AP_ID;
+	copyU16(tmpStr, protocolIe_Id);
+	buffer_copy(&g_value_buffer, tmpStr,
+					sizeof(protocolIe_Id));
+
+	uint8_t protocolIe_criticality = CRITICALITY_REJECT;
+	buffer_copy(&g_value_buffer, &protocolIe_criticality,
+					sizeof(protocolIe_criticality));
+
+	uint8_t datalen = 2;
+
+	/* TODO needs proper handling*/
+	unsigned char mme_ue_id[3];
+	datalen = copyU16(mme_ue_id,
+			s1apPDU.value.data[0].val.mme_ue_s1ap_id);
+	buffer_copy(&g_value_buffer, &datalen, sizeof(datalen));
+	buffer_copy(&g_value_buffer, mme_ue_id, datalen);
+
+	/* id-eNB-UE-S1AP-ID */
+
+	protocolIe_Id = id_eNB_UE_S1AP_ID;
+	copyU16(tmpStr, protocolIe_Id);
+	buffer_copy(&g_value_buffer, tmpStr,
+						sizeof(protocolIe_Id));
+
+	buffer_copy(&g_value_buffer, &protocolIe_criticality,
+					sizeof(protocolIe_criticality));
+
+
+	/* TODO needs proper handling*/
+	unsigned char enb_ue_id[3];
+	datalen = copyU16(enb_ue_id,
+			s1apPDU.value.data[1].val.enb_ue_s1ap_id);
+	buffer_copy(&g_value_buffer, &datalen, sizeof(datalen));
+	buffer_copy(&g_value_buffer, enb_ue_id, datalen);
+
+	/* id-NAS-PDU */
+	protocolIe_Id = id_NAS_PDU;
+	copyU16(tmpStr, protocolIe_Id);
+	buffer_copy(&g_value_buffer, tmpStr,
+						sizeof(protocolIe_Id));
+
+	buffer_copy(&g_value_buffer, &protocolIe_criticality,
+					sizeof(protocolIe_criticality));
+
+	struct nasPDU *nas = &(s1apPDU.value.data[2].val.nas);
+	uint8_t value = (nas->header.security_header_type) |
+			nas->header.proto_discriminator;
+
+	g_nas_buffer.pos = 0;
+
+	buffer_copy(&g_nas_buffer, &value, sizeof(value));
+
+	buffer_copy(&g_nas_buffer, &nas->header.message_type,
+						sizeof(nas->header.message_type));
+
+#if 0
+	buffer_copy(&g_nas_buffer, &nas->header.nas_security_param,
+						sizeof(nas->header.nas_security_param));
+
+#endif
+    value = 0x09; // UE identity can not be derived by the network
+	buffer_copy(&g_nas_buffer, &value, sizeof(value));
+
+#if 0
+	buffer_copy(&g_nas_buffer, &nas->elements[0].pduElement.rand,
+						sizeof(nas->elements[0].pduElement.rand));
+
+	datalen = 16;
+	buffer_copy(&g_nas_buffer, &datalen, sizeof(datalen));
+
+	buffer_copy(&g_nas_buffer, &nas->elements[1].pduElement.autn,
+						sizeof(nas->elements[1].pduElement.autn));
+
+    /* Done with filling NAS message */
+#endif
+	datalen = g_nas_buffer.pos + 1;
+
+	buffer_copy(&g_value_buffer, &datalen,
+						sizeof(datalen));
+
+	buffer_copy(&g_value_buffer, &g_nas_buffer.pos,
+						sizeof(g_nas_buffer.pos));
+
+
+	buffer_copy(&g_value_buffer, &g_nas_buffer,
+						g_nas_buffer.pos);
+
+	buffer_copy(&g_buffer, &g_value_buffer.pos,
+						sizeof(g_value_buffer.pos));
+
+	buffer_copy(&g_buffer, &g_value_buffer,
+						g_value_buffer.pos);
+
+	free(s1apPDU.value.data[2].val.nas.elements);
+	free(s1apPDU.value.data);
+	send_sctp_msg(g_attachReqRejInfo->enb_fd, g_buffer.buf, g_buffer.pos,1);
+	return SUCCESS;
+}
+
+
+void*
+attach_reject_handler(void *data)
+{
+	
+	log_msg(LOG_INFO, "S1Ap attach Reject handler ready.\n");
+
+s1ap_attach_reject_processing((struct attachReqRej_info *)data);
+
+	
+	return NULL;
+}
+