diff --git a/src/thread_list.h b/src/thread_list.h
new file mode 100644
index 0000000..12fdde4
--- /dev/null
+++ b/src/thread_list.h
@@ -0,0 +1,88 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ART_SRC_THREAD_LIST_H_
+#define ART_SRC_THREAD_LIST_H_
+
+#include "mutex.h"
+#include "thread.h"
+
+namespace art {
+
+class ThreadList {
+ public:
+  static const uint32_t kMaxThreadId = 0xFFFF;
+  static const uint32_t kInvalidId = 0;
+  static const uint32_t kMainId = 1;
+
+  ThreadList();
+  ~ThreadList();
+
+  void Dump(std::ostream& os);
+
+  void Register(Thread* thread);
+
+  void Unregister();
+
+  bool Contains(Thread* thread);
+
+  void VisitRoots(Heap::RootVisitor* visitor, void* arg) const;
+
+ private:
+  uint32_t AllocThreadId();
+  void ReleaseThreadId(uint32_t id);
+
+  mutable Mutex lock_;
+  std::bitset<kMaxThreadId> allocated_ids_;
+  std::list<Thread*> list_;
+
+  friend class Thread;
+  friend class ThreadListLock;
+
+  DISALLOW_COPY_AND_ASSIGN(ThreadList);
+};
+
+class ThreadListLock {
+ public:
+  ThreadListLock(Thread* self = NULL) {
+    if (self == NULL) {
+      // Try to get it from TLS.
+      self = Thread::Current();
+    }
+    Thread::State old_state;
+    if (self != NULL) {
+      old_state = self->SetState(Thread::kWaiting);  // TODO: VMWAIT
+    } else {
+      // This happens during VM shutdown.
+      old_state = Thread::kUnknown;
+    }
+    Runtime::Current()->GetThreadList()->lock_.Lock();
+    if (self != NULL) {
+      self->SetState(old_state);
+    }
+  }
+
+  ~ThreadListLock() {
+    Runtime::Current()->GetThreadList()->lock_.Unlock();
+  }
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(ThreadListLock);
+};
+
+}  // namespace art
+
+#endif  // ART_SRC_THREAD_LIST_H_