diff --git a/runtime/vm/os_thread_macos.cc b/runtime/vm/os_thread_macos.cc
index 50a2952..a0d050e 100644
--- a/runtime/vm/os_thread_macos.cc
+++ b/runtime/vm/os_thread_macos.cc
@@ -88,20 +88,6 @@
   DISALLOW_COPY_AND_ASSIGN(ThreadStartData);
 };
 
-// Spawned threads inherit their spawner's signal mask. We sometimes spawn
-// threads for running Dart code from a thread that is blocking SIGPROF.
-// This function explicitly unblocks SIGPROF so the profiler continues to
-// sample this thread.
-static void UnblockSIGPROF() {
-  sigset_t set;
-  sigemptyset(&set);
-  sigaddset(&set, SIGPROF);
-  int r = pthread_sigmask(SIG_UNBLOCK, &set, NULL);
-  USE(r);
-  ASSERT(r == 0);
-  ASSERT(!CHECK_IS_BLOCKING(SIGPROF));
-}
-
 // Dispatch to the thread start function provided by the caller. This trampoline
 // is used to ensure that the thread is properly destroyed if the thread just
 // exits.
@@ -121,7 +107,6 @@
   if (thread != NULL) {
     OSThread::SetCurrent(thread);
     thread->set_name(name);
-    UnblockSIGPROF();
     // Call the supplied thread start function handing it its parameters.
     function(parameter);
   }