diff --git a/runtime/lib/class_id.cc b/runtime/lib/class_id.cc
deleted file mode 100644
index c0f5295bd82..00000000000
--- a/runtime/lib/class_id.cc
+++ /dev/null
@@ -1,16 +0,0 @@
-// Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-#include "platform/assert.h"
-#include "vm/bootstrap_natives.h"
-
-namespace dart {
-
-DEFINE_NATIVE_ENTRY(ClassID_getID, 0, 1) {
-  const Instance& instance =
-      Instance::CheckedHandle(zone, arguments->NativeArgAt(0));
-  return Smi::New(instance.GetClassId());
-}
-
-}  // namespace dart
diff --git a/runtime/lib/internal_sources.gni b/runtime/lib/internal_sources.gni
deleted file mode 100644
index b16eafe80ca..00000000000
--- a/runtime/lib/internal_sources.gni
+++ /dev/null
@@ -1,6 +0,0 @@
-# Copyright (c) 2017, the Dart project authors.  Please see the AUTHORS file
-# for details. All rights reserved. Use of this source code is governed by a
-# BSD-style license that can be found in the LICENSE file.
-
-# Sources that patch the library "dart:_internal".
-internal_runtime_cc_files = [ "class_id.cc" ]
diff --git a/runtime/vm/BUILD.gn b/runtime/vm/BUILD.gn
index ab184be6d7a..69dfc4bff05 100644
--- a/runtime/vm/BUILD.gn
+++ b/runtime/vm/BUILD.gn
@@ -25,7 +25,6 @@ import("../lib/convert_sources.gni")
 import("../lib/core_sources.gni")
 import("../lib/developer_sources.gni")
 import("../lib/ffi_sources.gni")
-import("../lib/internal_sources.gni")
 import("../lib/isolate_sources.gni")
 import("../lib/math_sources.gni")
 import("../lib/mirrors_sources.gni")
@@ -153,10 +152,10 @@ library_for_all_configs("libdart_lib") {
   }
   include_dirs = [ ".." ]
   allsources = async_runtime_cc_files + core_runtime_cc_files +
-               developer_runtime_cc_files + internal_runtime_cc_files +
-               isolate_runtime_cc_files + math_runtime_cc_files +
-               mirrors_runtime_cc_files + typed_data_runtime_cc_files +
-               vmservice_runtime_cc_files + ffi_runtime_cc_files
+               developer_runtime_cc_files + isolate_runtime_cc_files +
+               math_runtime_cc_files + mirrors_runtime_cc_files +
+               typed_data_runtime_cc_files + vmservice_runtime_cc_files +
+               ffi_runtime_cc_files
   sources = [ "bootstrap.cc" ] + rebase_path(allsources, ".", "../lib")
   snapshot_sources = []
 }
diff --git a/runtime/vm/bootstrap_natives.h b/runtime/vm/bootstrap_natives.h
index 717040f22ca..4911d25fc68 100644
--- a/runtime/vm/bootstrap_natives.h
+++ b/runtime/vm/bootstrap_natives.h
@@ -356,7 +356,6 @@ namespace dart {
   V(UserTag_defaultTag, 0)                                                     \
   V(UserTag_makeCurrent, 1)                                                    \
   V(Profiler_getCurrentTag, 0)                                                 \
-  V(ClassID_getID, 1)                                                          \
   V(VMService_SendIsolateServiceMessage, 2)                                    \
   V(VMService_SendRootServiceMessage, 1)                                       \
   V(VMService_SendObjectRootServiceMessage, 1)                                 \
diff --git a/sdk/lib/_internal/vm/lib/class_id.dart b/sdk/lib/_internal/vm/lib/class_id.dart
deleted file mode 100644
index ff9d0b6d329..00000000000
--- a/sdk/lib/_internal/vm/lib/class_id.dart
+++ /dev/null
@@ -1,14 +0,0 @@
-// Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-// part of "internal_patch.dart";
-
-@pragma("vm:entry-point")
-class ClassID {
-  @pragma("vm:entry-point")
-  @pragma("vm:exact-result-type", "dart:core#_Smi")
-  static int getID(Object value) native "ClassID_getID";
-
-  // VM injects class id constants into this class.
-}