diff --git a/utils.go b/utils.go
index 81715881ae..1393a5c0a8 100644
--- a/utils.go
+++ b/utils.go
@@ -89,6 +89,15 @@ func MergeConfig(userConf, imageConf *Config) error {
 	}
 	if userConf.ExposedPorts == nil || len(userConf.ExposedPorts) == 0 {
 		userConf.ExposedPorts = imageConf.ExposedPorts
+	} else if imageConf.ExposedPorts != nil {
+		if userConf.ExposedPorts == nil {
+			userConf.ExposedPorts = make(map[Port]struct{})
+		}
+		for port := range imageConf.ExposedPorts {
+			if _, exists := userConf.ExposedPorts[port]; !exists {
+				userConf.ExposedPorts[port] = struct{}{}
+			}
+		}
 	}
 
 	if userConf.PortSpecs != nil && len(userConf.PortSpecs) > 0 {
diff --git a/utils_test.go b/utils_test.go
index 87426f38ea..589cd405ea 100644
--- a/utils_test.go
+++ b/utils_test.go
@@ -247,7 +247,9 @@ func TestMergeConfig(t *testing.T) {
 		Volumes:   volumesUser,
 	}
 
-	MergeConfig(configUser, configImage)
+	if err := MergeConfig(configUser, configImage); err != nil {
+		t.Error(err)
+	}
 
 	if len(configUser.Dns) != 3 {
 		t.Fatalf("Expected 3 dns, 1.1.1.1, 2.2.2.2 and 3.3.3.3, found %d", len(configUser.Dns))
@@ -259,7 +261,7 @@ func TestMergeConfig(t *testing.T) {
 	}
 
 	if len(configUser.ExposedPorts) != 3 {
-		t.Fatalf("Expected 3 portSpecs, 1111, 2222 and 3333, found %d", len(configUser.PortSpecs))
+		t.Fatalf("Expected 3 ExposedPorts, 1111, 2222 and 3333, found %d", len(configUser.ExposedPorts))
 	}
 	for portSpecs := range configUser.ExposedPorts {
 		if portSpecs.Port() != "1111" && portSpecs.Port() != "2222" && portSpecs.Port() != "3333" {
@@ -287,6 +289,28 @@ func TestMergeConfig(t *testing.T) {
 	if configUser.VolumesFrom != "1111" {
 		t.Fatalf("Expected VolumesFrom to be 1111, found %s", configUser.VolumesFrom)
 	}
+
+	ports, _, err := parsePortSpecs([]string{"0000"})
+	if err != nil {
+		t.Error(err)
+	}
+	configImage2 := &Config{
+		ExposedPorts: ports,
+	}
+
+	if err := MergeConfig(configUser, configImage2); err != nil {
+		t.Error(err)
+	}
+
+	if len(configUser.ExposedPorts) != 4 {
+		t.Fatalf("Expected 4 ExposedPorts, 0000, 1111, 2222 and 3333, found %d", len(configUser.ExposedPorts))
+	}
+	for portSpecs := range configUser.ExposedPorts {
+		if portSpecs.Port() != "0000" && portSpecs.Port() != "1111" && portSpecs.Port() != "2222" && portSpecs.Port() != "3333" {
+			t.Fatalf("Expected 0000 or 1111 or 2222 or 3333, found %s", portSpecs)
+		}
+	}
+
 }
 
 func TestParseLxcConfOpt(t *testing.T) {