diff --git a/adapters/bidder.go b/adapters/bidder.go
index 622be8212f5..2ac2271fc07 100644
--- a/adapters/bidder.go
+++ b/adapters/bidder.go
@@ -130,7 +130,8 @@ type ExtImpBidder struct {
 	//
 	// Bidder implementations may safely assume that this JSON has been validated by their
 	// static/bidder-params/{bidder}.json file.
-	Bidder json.RawMessage `json:"bidder"`
+	Bidder json.RawMessage      `json:"bidder"`
+	Data   *openrtb_ext.ExtData `json:"data,omitempty"`
 }
 
 func (r *RequestData) SetBasicAuth(username string, password string) {
diff --git a/adapters/pubmatic/pubmatic.go b/adapters/pubmatic/pubmatic.go
index c9e3660b4c8..a0ca5f50529 100644
--- a/adapters/pubmatic/pubmatic.go
+++ b/adapters/pubmatic/pubmatic.go
@@ -28,6 +28,8 @@ const (
 	buyIdTargetingKey        = "hb_buyid_pubmatic"
 	skAdnetworkKey           = "skadn"
 	rewardKey                = "reward"
+	ImpExtAdUnitKey          = "dfp_ad_unit_code"
+	AdServerGAM              = "gam"
 )
 
 type PubmaticAdapter struct {
@@ -631,6 +633,11 @@ func parseImpressionObject(imp *openrtb2.Imp, wrapExt *pubmaticWrapperExt, pubID
 		}
 	}
 
+	if bidderExt.Data != nil && bidderExt.Data.AdServer != nil &&
+		bidderExt.Data.AdServer.Name == AdServerGAM && bidderExt.Data.AdServer.AdSlot != "" {
+		impExtMap[ImpExtAdUnitKey] = bidderExt.Data.AdServer.AdSlot
+	}
+
 	if len(impExtMap) != 0 {
 		impExtBytes, err := json.Marshal(impExtMap)
 		if err == nil {
diff --git a/adapters/pubmatic/pubmatictest/supplemental/gptSlotNameInImpExt.json b/adapters/pubmatic/pubmatictest/supplemental/gptSlotNameInImpExt.json
new file mode 100644
index 00000000000..9336ed63262
--- /dev/null
+++ b/adapters/pubmatic/pubmatictest/supplemental/gptSlotNameInImpExt.json
@@ -0,0 +1,174 @@
+{
+  "mockBidRequest": {
+    "id": "test-request-id",
+    "imp": [
+      {
+        "id": "test-imp-id",
+        "banner": {
+          "format": [
+            {
+              "w": 300,
+              "h": 250
+            }
+          ]
+        },
+        "ext": {
+          "bidder": {
+            "adSlot": "AdTag_Div1@300x250",
+            "publisherId": "999",
+            "keywords": [
+              {
+                "key": "pmZoneID",
+                "value": [
+                  "Zone1",
+                  "Zone2"
+                ]
+              },
+              {
+                "key": "preference",
+                "value": [
+                  "sports",
+                  "movies"
+                ]
+              }
+            ],
+            "wrapper": {
+              "version": 1,
+              "profile": 5123
+            }
+          },
+          "data": {
+            "adserver": {
+              "name": "gam",
+              "adslot": "/1111/home"
+            }
+          }
+        }
+      }
+    ],
+    "device": {
+      "ua": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/63.0.3239.132 Safari/537.36"
+    },
+    "site": {
+      "id": "siteID",
+      "publisher": {
+        "id": "1234"
+      }
+    },
+    "ext": {
+      "prebid": {
+        "bidderparams": {
+          "wiid": "dwzafakjflan-tygannnvlla-mlljvj"
+        }
+      }
+    }
+  },
+  "httpCalls": [
+    {
+      "expectedRequest": {
+        "uri": "https://hbopenbid.pubmatic.com/translator?source=prebid-server",
+        "body": {
+          "id": "test-request-id",
+          "imp": [
+            {
+              "id": "test-imp-id",
+              "tagid": "AdTag_Div1",
+              "banner": {
+                "format": [
+                  {
+                    "w": 300,
+                    "h": 250
+                  }
+                ],
+                "h": 250,
+                "w": 300
+              },
+              "ext": {
+                "pmZoneID": "Zone1,Zone2",
+                "preference": "sports,movies",
+                "dfp_ad_unit_code": "/1111/home"
+              }
+            }
+          ],
+          "device": {
+            "ua": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/63.0.3239.132 Safari/537.36"
+          },
+          "site": {
+            "id": "siteID",
+            "publisher": {
+              "id": "999"
+            }
+          },
+          "ext": {
+            "wrapper": {
+              "profile": 5123,
+              "version": 1,
+              "wiid": "dwzafakjflan-tygannnvlla-mlljvj"
+            }
+          }
+        }
+      },
+      "mockResponse": {
+        "status": 200,
+        "body": {
+          "id": "test-request-id",
+          "seatbid": [
+            {
+              "seat": "958",
+              "bid": [
+                {
+                  "id": "7706636740145184841",
+                  "impid": "test-imp-id",
+                  "price": 0.500000,
+                  "adid": "29681110",
+                  "adm": "some-test-ad",
+                  "adomain": [
+                    "pubmatic.com"
+                  ],
+                  "crid": "29681110",
+                  "h": 250,
+                  "w": 300,
+                  "dealid": "test deal",
+                  "ext": {
+                    "dspid": 6,
+                    "deal_channel": 1
+                  }
+                }
+              ]
+            }
+          ],
+          "bidid": "5778926625248726496",
+          "cur": "USD"
+        }
+      }
+    }
+  ],
+  "expectedBidResponses": [
+    {
+      "currency": "USD",
+      "bids": [
+        {
+          "bid": {
+            "id": "7706636740145184841",
+            "impid": "test-imp-id",
+            "price": 0.5,
+            "adid": "29681110",
+            "adm": "some-test-ad",
+            "adomain": [
+              "pubmatic.com"
+            ],
+            "crid": "29681110",
+            "w": 300,
+            "h": 250,
+            "dealid": "test deal",
+            "ext": {
+              "dspid": 6,
+              "deal_channel": 1
+            }
+          },
+          "type": "banner"
+        }
+      ]
+    }
+  ]
+}
diff --git a/openrtb_ext/imp.go b/openrtb_ext/imp.go
index f83fa63df84..4a2c2bc5c77 100644
--- a/openrtb_ext/imp.go
+++ b/openrtb_ext/imp.go
@@ -22,3 +22,12 @@ type ExtImpPrebid struct {
 type ExtStoredRequest struct {
 	ID string `json:"id"`
 }
+
+type ExtData struct {
+	AdServer *ExtAdServer `json:"adserver"`
+}
+
+type ExtAdServer struct {
+	Name   string `json:"name"`
+	AdSlot string `json:"adslot"`
+}