diff --git a/reactos/dll/win32/samsrv/samrpc.c b/reactos/dll/win32/samsrv/samrpc.c
index 6d7a257a1ed..dcdb4cef3d3 100644
--- a/reactos/dll/win32/samsrv/samrpc.c
+++ b/reactos/dll/win32/samsrv/samrpc.c
@@ -4158,8 +4158,30 @@ SamrSetMemberAttributesOfGroup(IN SAMPR_HANDLE GroupHandle,
                                IN unsigned long MemberId,
                                IN unsigned long Attributes)
 {
-    UNIMPLEMENTED;
-    return STATUS_NOT_IMPLEMENTED;
+    PSAM_DB_OBJECT GroupObject;
+    NTSTATUS Status;
+
+    /* Validate the group handle */
+    Status = SampValidateDbObject(GroupHandle,
+                                  SamDbGroupObject,
+                                  GROUP_ADD_MEMBER,
+                                  &GroupObject);
+    if (!NT_SUCCESS(Status))
+    {
+        TRACE("SampValidateDbObject failed with status 0x%08lx\n", Status);
+        return Status;
+    }
+
+    Status = SampSetUserGroupAttributes(GroupObject->ParentObject,
+                                        MemberId,
+                                        GroupObject->RelativeId,
+                                        Attributes);
+    if (!NT_SUCCESS(Status))
+    {
+        TRACE("SampSetUserGroupAttributes failed with status 0x%08lx\n", Status);
+    }
+
+    return Status;
 }
 
 
diff --git a/reactos/dll/win32/samsrv/samsrv.h b/reactos/dll/win32/samsrv/samsrv.h
index 7de5ce15cfb..c07d0ea40a1 100644
--- a/reactos/dll/win32/samsrv/samsrv.h
+++ b/reactos/dll/win32/samsrv/samsrv.h
@@ -285,4 +285,10 @@ SampGetUserGroupAttributes(IN PSAM_DB_OBJECT DomainObject,
                            IN ULONG GroupId,
                            OUT PULONG GroupAttributes);
 
+NTSTATUS
+SampSetUserGroupAttributes(IN PSAM_DB_OBJECT DomainObject,
+                           IN ULONG UserId,
+                           IN ULONG GroupId,
+                           IN ULONG GroupAttributes);
+
 /* EOF */
diff --git a/reactos/dll/win32/samsrv/user.c b/reactos/dll/win32/samsrv/user.c
index f3174c627a5..0805e4475e0 100644
--- a/reactos/dll/win32/samsrv/user.c
+++ b/reactos/dll/win32/samsrv/user.c
@@ -214,10 +214,7 @@ SampGetUserGroupAttributes(IN PSAM_DB_OBJECT DomainObject,
                            &Length);
 
     if (Length == 0)
-    {
-        *GroupAttributes = 0;
-        return STATUS_SUCCESS;
-    }
+        return STATUS_UNSUCCESSFUL; /* FIXME */
 
     GroupsBuffer = midl_user_allocate(Length);
     if (GroupsBuffer == NULL)
@@ -253,4 +250,75 @@ done:
     return Status;
 }
 
+
+NTSTATUS
+SampSetUserGroupAttributes(IN PSAM_DB_OBJECT DomainObject,
+                           IN ULONG UserId,
+                           IN ULONG GroupId,
+                           IN ULONG GroupAttributes)
+{
+    PSAM_DB_OBJECT UserObject = NULL;
+    PGROUP_MEMBERSHIP GroupsBuffer = NULL;
+    ULONG Length = 0;
+    ULONG i;
+    NTSTATUS Status;
+
+    Status = SampOpenUserObject(DomainObject,
+                                UserId,
+                                0,
+                                &UserObject);
+    if (!NT_SUCCESS(Status))
+    {
+        return Status;
+    }
+
+    SampGetObjectAttribute(UserObject,
+                           L"Groups",
+                           NULL,
+                           NULL,
+                           &Length);
+
+    if (Length == 0)
+        return STATUS_UNSUCCESSFUL; /* FIXME */
+
+    GroupsBuffer = midl_user_allocate(Length);
+    if (GroupsBuffer == NULL)
+    {
+        Status = STATUS_INSUFFICIENT_RESOURCES;
+        goto done;
+    }
+
+    Status = SampGetObjectAttribute(UserObject,
+                                    L"Groups",
+                                    NULL,
+                                    GroupsBuffer,
+                                    &Length);
+    if (!NT_SUCCESS(Status))
+        goto done;
+
+    for (i = 0; i < (Length / sizeof(GROUP_MEMBERSHIP)); i++)
+    {
+        if (GroupsBuffer[i].RelativeId == GroupId)
+        {
+            GroupsBuffer[i].Attributes = GroupAttributes;
+            break;
+        }
+    }
+
+    Status = SampSetObjectAttribute(UserObject,
+                                    L"Groups",
+                                    REG_BINARY,
+                                    GroupsBuffer,
+                                    Length);
+
+done:
+    if (GroupsBuffer != NULL)
+        midl_user_free(GroupsBuffer);
+
+    if (UserObject != NULL)
+        SampCloseDbObject(UserObject);
+
+    return Status;
+}
+
 /* EOF */