diff --git a/staging/src/k8s.io/legacy-cloud-providers/azure/azure_managedDiskController.go b/staging/src/k8s.io/legacy-cloud-providers/azure/azure_managedDiskController.go
index 78fd2468ee0..e93401eb504 100644
--- a/staging/src/k8s.io/legacy-cloud-providers/azure/azure_managedDiskController.go
+++ b/staging/src/k8s.io/legacy-cloud-providers/azure/azure_managedDiskController.go
@@ -297,6 +297,10 @@ func (c *ManagedDiskController) ResizeDisk(diskURI string, oldSize resource.Quan
 		return newSizeQuant, nil
 	}
 
+	if result.DiskProperties.DiskState != compute.Unattached {
+		return oldSize, fmt.Errorf("azureDisk - disk resize is only supported on Unattached disk, current disk state: %s, already attached to %s", result.DiskProperties.DiskState, to.String(result.ManagedBy))
+	}
+
 	diskParameter := compute.DiskUpdate{
 		DiskUpdateProperties: &compute.DiskUpdateProperties{
 			DiskSizeGB: &requestGiB,
diff --git a/staging/src/k8s.io/legacy-cloud-providers/azure/azure_managedDiskController_test.go b/staging/src/k8s.io/legacy-cloud-providers/azure/azure_managedDiskController_test.go
index 1e40eeb4933..7ead4f5cf27 100644
--- a/staging/src/k8s.io/legacy-cloud-providers/azure/azure_managedDiskController_test.go
+++ b/staging/src/k8s.io/legacy-cloud-providers/azure/azure_managedDiskController_test.go
@@ -311,7 +311,7 @@ func TestResizeDisk(t *testing.T) {
 			diskName:         diskName,
 			oldSize:          *resource.NewQuantity(2*(1024*1024*1024), resource.BinarySI),
 			newSize:          *resource.NewQuantity(3*(1024*1024*1024), resource.BinarySI),
-			existedDisk:      compute.Disk{Name: to.StringPtr("disk1"), DiskProperties: &compute.DiskProperties{DiskSizeGB: &diskSizeGB}},
+			existedDisk:      compute.Disk{Name: to.StringPtr("disk1"), DiskProperties: &compute.DiskProperties{DiskSizeGB: &diskSizeGB, DiskState: compute.Unattached}},
 			expectedQuantity: *resource.NewQuantity(3*(1024*1024*1024), resource.BinarySI),
 			expectedErr:      false,
 		},
@@ -330,7 +330,7 @@ func TestResizeDisk(t *testing.T) {
 			diskName:         diskName,
 			oldSize:          *resource.NewQuantity(1*(1024*1024*1024), resource.BinarySI),
 			newSize:          *resource.NewQuantity(2*(1024*1024*1024), resource.BinarySI),
-			existedDisk:      compute.Disk{Name: to.StringPtr("disk1"), DiskProperties: &compute.DiskProperties{DiskSizeGB: &diskSizeGB}},
+			existedDisk:      compute.Disk{Name: to.StringPtr("disk1"), DiskProperties: &compute.DiskProperties{DiskSizeGB: &diskSizeGB, DiskState: compute.Unattached}},
 			expectedQuantity: *resource.NewQuantity(2*(1024*1024*1024), resource.BinarySI),
 			expectedErr:      false,
 		},
@@ -339,7 +339,7 @@ func TestResizeDisk(t *testing.T) {
 			diskName:         fakeGetDiskFailed,
 			oldSize:          *resource.NewQuantity(2*(1024*1024*1024), resource.BinarySI),
 			newSize:          *resource.NewQuantity(3*(1024*1024*1024), resource.BinarySI),
-			existedDisk:      compute.Disk{Name: to.StringPtr(fakeGetDiskFailed), DiskProperties: &compute.DiskProperties{DiskSizeGB: &diskSizeGB}},
+			existedDisk:      compute.Disk{Name: to.StringPtr(fakeGetDiskFailed), DiskProperties: &compute.DiskProperties{DiskSizeGB: &diskSizeGB, DiskState: compute.Unattached}},
 			expectedQuantity: *resource.NewQuantity(2*(1024*1024*1024), resource.BinarySI),
 			expectedErr:      true,
 			expectedErrMsg:   fmt.Errorf("Retriable: false, RetryAfter: 0s, HTTPStatusCode: 0, RawError: Get Disk failed"),
@@ -349,11 +349,21 @@ func TestResizeDisk(t *testing.T) {
 			diskName:         fakeCreateDiskFailed,
 			oldSize:          *resource.NewQuantity(2*(1024*1024*1024), resource.BinarySI),
 			newSize:          *resource.NewQuantity(3*(1024*1024*1024), resource.BinarySI),
-			existedDisk:      compute.Disk{Name: to.StringPtr(fakeCreateDiskFailed), DiskProperties: &compute.DiskProperties{DiskSizeGB: &diskSizeGB}},
+			existedDisk:      compute.Disk{Name: to.StringPtr(fakeCreateDiskFailed), DiskProperties: &compute.DiskProperties{DiskSizeGB: &diskSizeGB, DiskState: compute.Unattached}},
 			expectedQuantity: *resource.NewQuantity(2*(1024*1024*1024), resource.BinarySI),
 			expectedErr:      true,
 			expectedErrMsg:   fmt.Errorf("Retriable: false, RetryAfter: 0s, HTTPStatusCode: 0, RawError: Create Disk failed"),
 		},
+		{
+			desc:             "an error shall be returned if disk is not in Unattached state",
+			diskName:         fakeCreateDiskFailed,
+			oldSize:          *resource.NewQuantity(2*(1024*1024*1024), resource.BinarySI),
+			newSize:          *resource.NewQuantity(3*(1024*1024*1024), resource.BinarySI),
+			existedDisk:      compute.Disk{Name: to.StringPtr(fakeCreateDiskFailed), DiskProperties: &compute.DiskProperties{DiskSizeGB: &diskSizeGB, DiskState: compute.Attached}},
+			expectedQuantity: *resource.NewQuantity(2*(1024*1024*1024), resource.BinarySI),
+			expectedErr:      true,
+			expectedErrMsg:   fmt.Errorf("azureDisk - disk resize is only supported on Unattached disk, current disk state: Attached, already attached to "),
+		},
 	}
 
 	for i, test := range testCases {