diff --git a/azurerm/resource_arm_app_service.go b/azurerm/resource_arm_app_service.go
index 8b07bd0a621d..deb0c5c56df6 100644
--- a/azurerm/resource_arm_app_service.go
+++ b/azurerm/resource_arm_app_service.go
@@ -267,7 +267,7 @@ func resourceArmAppServiceCreate(d *schema.ResourceData, meta interface{}) error
 		},
 	}
 
-	if v, ok := d.GetOk("client_affinity_enabled"); ok {
+	if v, ok := d.GetOkExists("client_affinity_enabled"); ok {
 		enabled := v.(bool)
 		siteEnvelope.SiteProperties.ClientAffinityEnabled = utils.Bool(enabled)
 	}
diff --git a/azurerm/resource_arm_app_service_test.go b/azurerm/resource_arm_app_service_test.go
index ceb04ea2015e..768cb122bc1b 100644
--- a/azurerm/resource_arm_app_service_test.go
+++ b/azurerm/resource_arm_app_service_test.go
@@ -194,6 +194,27 @@ func TestAccAzureRMAppService_clientAffinityEnabled(t *testing.T) {
 	})
 }
 
+func TestAccAzureRMAppService_clientAffinityDisabled(t *testing.T) {
+	resourceName := "azurerm_app_service.test"
+	ri := acctest.RandInt()
+	config := testAccAzureRMAppService_clientAffinityDisabled(ri, testLocation())
+
+	resource.Test(t, resource.TestCase{
+		PreCheck:     func() { testAccPreCheck(t) },
+		Providers:    testAccProviders,
+		CheckDestroy: testCheckAzureRMAppServiceDestroy,
+		Steps: []resource.TestStep{
+			{
+				Config: config,
+				Check: resource.ComposeTestCheckFunc(
+					testCheckAzureRMAppServiceExists(resourceName),
+					resource.TestCheckResourceAttr(resourceName, "client_affinity_enabled", "false"),
+				),
+			},
+		},
+	})
+}
+
 func TestAccAzureRMAppService_connectionStrings(t *testing.T) {
 	resourceName := "azurerm_app_service.test"
 	ri := acctest.RandInt()
@@ -846,6 +867,34 @@ resource "azurerm_app_service" "test" {
 `, rInt, location, rInt, rInt)
 }
 
+func testAccAzureRMAppService_clientAffinityDisabled(rInt int, location string) string {
+	return fmt.Sprintf(`
+resource "azurerm_resource_group" "test" {
+  name = "acctestRG-%d"
+  location = "%s"
+}
+
+resource "azurerm_app_service_plan" "test" {
+  name                = "acctestASP-%d"
+  location            = "${azurerm_resource_group.test.location}"
+  resource_group_name = "${azurerm_resource_group.test.name}"
+
+  sku {
+    tier = "Standard"
+    size = "S1"
+  }
+}
+
+resource "azurerm_app_service" "test" {
+  name                    = "acctestAS-%d"
+  location                = "${azurerm_resource_group.test.location}"
+  resource_group_name     = "${azurerm_resource_group.test.name}"
+  app_service_plan_id     = "${azurerm_app_service_plan.test.id}"
+  client_affinity_enabled = false
+}
+`, rInt, location, rInt, rInt)
+}
+
 func testAccAzureRMAppService_connectionStrings(rInt int, location string) string {
 	return fmt.Sprintf(`
 resource "azurerm_resource_group" "test" {