diff --git a/adaptercore/device_handler.go b/adaptercore/device_handler.go
index 60c128a..447079d 100644
--- a/adaptercore/device_handler.go
+++ b/adaptercore/device_handler.go
@@ -1117,6 +1117,16 @@
 	}
 	return ""
 }
+func (dh *DeviceHandler) deStringifySerialNumber(serialNum string) (*oop.SerialNumber, error) {
+	decodedStr, err := hex.DecodeString(serialNum[4:])
+	if err != nil {
+		return nil, err
+	}
+	return &oop.SerialNumber{
+		VendorId:       []byte(serialNum[:4]),
+		VendorSpecific: []byte(decodedStr),
+	}, nil
+}
 
 func (dh *DeviceHandler) stringifyVendorSpecific(vendorSpecific []byte) string {
 	tmp := fmt.Sprintf("%x", (uint32(vendorSpecific[0])>>4)&0x0f) +
@@ -1755,3 +1765,64 @@
 		}
 	}
 }
+
+// ChildDeviceLost deletes ONU and clears pon resources related to it.
+func (dh *DeviceHandler) ChildDeviceLost(ctx context.Context, pPortNo uint32, onuID uint32) error {
+	log.Debugw("child-device-lost", log.Fields{"pdeviceID": dh.device.Id})
+	IntfID := PortNoToIntfID(pPortNo, voltha.Port_PON_OLT)
+	onuKey := dh.formOnuKey(IntfID, onuID)
+	onuDevice, ok := dh.onus.Load(onuKey)
+	if !ok {
+		return NewErrAdapter("failed-to-load-onu-details",
+			log.Fields{
+				"device-id":    dh.deviceID,
+				"onu-id":       onuID,
+				"interface-id": IntfID}, nil).Log()
+	}
+	var sn *oop.SerialNumber
+	var err error
+	if sn, err = dh.deStringifySerialNumber(onuDevice.(*OnuDevice).serialNumber); err != nil {
+		return NewErrAdapter("failed-to-destringify-serial-number",
+			log.Fields{
+				"devicer-id":    dh.deviceID,
+				"serial-number": onuDevice.(*OnuDevice).serialNumber}, err).Log()
+	}
+	onu := &oop.Onu{IntfId: IntfID, OnuId: onuID, SerialNumber: sn}
+	if _, err := dh.Client.DeleteOnu(context.Background(), onu); err != nil {
+		return NewErrAdapter("failed-to-delete-onu", log.Fields{
+			"device-id": dh.deviceID,
+			"onu-id":    onuID}, err).Log()
+	}
+	//clear PON resources associated with ONU
+	var onuGemData []rsrcMgr.OnuGemInfo
+	if err := dh.resourceMgr.ResourceMgrs[IntfID].GetOnuGemInfo(ctx, IntfID, &onuGemData); err != nil {
+		log.Errorw("Failed-to-get-onu-info-for-pon-port ", log.Fields{
+			"device-id":    dh.deviceID,
+			"interface-id": IntfID,
+			"error":        err})
+	}
+
+	for i, onu := range onuGemData {
+		if onu.OnuID == onuID && onu.SerialNumber == onuDevice.(*OnuDevice).serialNumber {
+			log.Debugw("onu-data ", log.Fields{"onu": onu})
+			if err := dh.clearUNIData(ctx, &onu); err != nil {
+				log.Errorw("Failed-to-clear-uni-data-for-onu", log.Fields{
+					"device-id":  dh.deviceID,
+					"onu-device": onu,
+					"error":      err})
+			}
+			// Clear flowids for gem cache.
+			for _, gem := range onu.GemPorts {
+				dh.resourceMgr.DeleteFlowIDsForGem(ctx, IntfID, gem)
+			}
+			onuGemData = append(onuGemData[:i], onuGemData[i+1:]...)
+			dh.resourceMgr.UpdateOnuGemInfo(ctx, IntfID, onuGemData)
+
+			dh.resourceMgr.FreeonuID(ctx, IntfID, []uint32{onu.OnuID})
+			break
+		}
+	}
+	dh.onus.Delete(onuKey)
+	dh.discOnus.Delete(onuDevice.(*OnuDevice).serialNumber)
+	return nil
+}