diff --git a/resource_compute_instance.go b/resource_compute_instance.go
index dd413440..3b54708f 100644
--- a/resource_compute_instance.go
+++ b/resource_compute_instance.go
@@ -361,6 +361,13 @@ func resourceComputeInstanceCreate(d *schema.ResourceData, meta interface{}) err
 		disk.Boot = i == 0
 		disk.AutoDelete = d.Get(prefix + ".auto_delete").(bool)
 
+		if _, ok := d.GetOk(prefix + ".disk"); ok {
+			if _, ok := d.GetOk(prefix + ".type"); ok {
+				return fmt.Errorf(
+					"Error: cannot define both disk and type.")
+			}
+		}
+
 		// Load up the disk for this disk if specified
 		if v, ok := d.GetOk(prefix + ".disk"); ok {
 			diskName := v.(string)
diff --git a/resource_compute_instance_test.go b/resource_compute_instance_test.go
index 7ea120e2..33b82aa7 100644
--- a/resource_compute_instance_test.go
+++ b/resource_compute_instance_test.go
@@ -2,6 +2,7 @@ package google
 
 import (
 	"fmt"
+	"regexp"
 	"strings"
 	"testing"
 
@@ -482,6 +483,23 @@ func TestAccComputeInstance_private_image_family(t *testing.T) {
 	})
 }
 
+func TestAccComputeInstance_invalid_disk(t *testing.T) {
+	var instanceName = fmt.Sprintf("instance-test-%s", acctest.RandString(10))
+	var diskName = fmt.Sprintf("instance-testd-%s", acctest.RandString(10))
+
+	resource.Test(t, resource.TestCase{
+		PreCheck:     func() { testAccPreCheck(t) },
+		Providers:    testAccProviders,
+		CheckDestroy: testAccCheckComputeInstanceDestroy,
+		Steps: []resource.TestStep{
+			resource.TestStep{
+				Config:      testAccComputeInstance_invalid_disk(diskName, instanceName),
+				ExpectError: regexp.MustCompile("Error: cannot define both disk and type."),
+			},
+		},
+	})
+}
+
 func testAccCheckComputeInstanceDestroy(s *terraform.State) error {
 	config := testAccProvider.Meta().(*Config)
 
@@ -1152,3 +1170,34 @@ func testAccComputeInstance_private_image_family(disk, image, family, instance s
 			}
 		}`, disk, image, family, instance)
 }
+
+func testAccComputeInstance_invalid_disk(disk, instance string) string {
+	return fmt.Sprintf(`
+		resource "google_compute_instance" "foobar" {
+		  name         = "%s"
+		  machine_type = "f1-micro"
+		  zone         = "us-central1-a"
+
+		  disk {
+		    image = "ubuntu-os-cloud/ubuntu-1604-lts"
+		    type  = "pd-standard"
+		  }
+
+		  disk {
+		    disk        = "${google_compute_disk.foobar.name}"
+		    type        = "pd-standard"
+		    device_name = "xvdb"
+		  }
+
+		  network_interface {
+		    network = "default"
+		  }
+		}
+
+		resource "google_compute_disk" "foobar" {
+		  name = "%s"
+		  zone = "us-central1-a"
+		  type = "pd-standard"
+		  size = "1"
+		}`, instance, disk)
+}