diff --git a/gunicorn/arbiter.py b/gunicorn/arbiter.py
index e5217266..80989ebe 100644
--- a/gunicorn/arbiter.py
+++ b/gunicorn/arbiter.py
@@ -515,8 +515,9 @@ class Arbiter(object):
                 if self.reexec_pid == wpid:
                     self.reexec_pid = 0
                 else:
-                    # A worker said it cannot boot. We'll shutdown
-                    # to avoid infinite start/stop cycles.
+                    # A worker was terminated. If the termination reason was
+                    # that it could not boot, we'll shut it down to avoid
+                    # infinite start/stop cycles.
                     exitcode = status >> 8
                     if exitcode == self.WORKER_BOOT_ERROR:
                         reason = "Worker failed to boot."
@@ -524,10 +525,12 @@ class Arbiter(object):
                     if exitcode == self.APP_LOAD_ERROR:
                         reason = "App failed to load."
                         raise HaltServer(reason, self.APP_LOAD_ERROR)
+
                     worker = self.WORKERS.pop(wpid, None)
                     if not worker:
                         continue
                     worker.tmp.close()
+                    self.cfg.child_exit(self, worker)
         except OSError as e:
             if e.errno != errno.ECHILD:
                 raise
@@ -562,14 +565,15 @@ class Arbiter(object):
         self.cfg.pre_fork(self, worker)
         pid = os.fork()
         if pid != 0:
+            worker.pid = pid
             self.WORKERS[pid] = worker
             return pid
 
         # Process Child
-        worker_pid = os.getpid()
+        worker.pid = os.getpid()
         try:
             util._setproctitle("worker [%s]" % self.proc_name)
-            self.log.info("Booting worker with pid: %s", worker_pid)
+            self.log.info("Booting worker with pid: %s", worker.pid)
             self.cfg.post_fork(self, worker)
             worker.init_process()
             sys.exit(0)
@@ -587,7 +591,7 @@ class Arbiter(object):
                 sys.exit(self.WORKER_BOOT_ERROR)
             sys.exit(-1)
         finally:
-            self.log.info("Worker exiting (pid: %s)", worker_pid)
+            self.log.info("Worker exiting (pid: %s)", worker.pid)
             try:
                 worker.tmp.close()
                 self.cfg.worker_exit(self, worker)
diff --git a/gunicorn/config.py b/gunicorn/config.py
index 442f737c..37eae21e 100644
--- a/gunicorn/config.py
+++ b/gunicorn/config.py
@@ -1650,6 +1650,23 @@ class PostRequest(Setting):
         """
 
 
+class ChildExit(Setting):
+    name = "child_exit"
+    section = "Server Hooks"
+    validator = validate_callable(2)
+    type = six.callable
+
+    def child_exit(server, worker):
+        pass
+    default = staticmethod(child_exit)
+    desc = """\
+        Called just after a worker has been exited, in the master process.
+
+        The callable needs to accept two instance variables for the Arbiter and
+        the just-exited Worker.
+        """
+
+
 class WorkerExit(Setting):
     name = "worker_exit"
     section = "Server Hooks"
@@ -1660,7 +1677,7 @@ class WorkerExit(Setting):
         pass
     default = staticmethod(worker_exit)
     desc = """\
-        Called just after a worker has been exited.
+        Called just after a worker has been exited, in the worker process.
 
         The callable needs to accept two instance variables for the Arbiter and
         the just-exited Worker.
diff --git a/gunicorn/workers/base.py b/gunicorn/workers/base.py
index b4f24e6a..aeec3a2e 100644
--- a/gunicorn/workers/base.py
+++ b/gunicorn/workers/base.py
@@ -39,6 +39,7 @@ class Worker(object):
         changes you'll want to do that in ``self.init_process()``.
         """
         self.age = age
+        self.pid = "[booting]"
         self.ppid = ppid
         self.sockets = sockets
         self.app = app
@@ -58,10 +59,6 @@ class Worker(object):
     def __str__(self):
         return "<Worker %s>" % self.pid
 
-    @property
-    def pid(self):
-        return os.getpid()
-
     def notify(self):
         """\
         Your worker subclass must arrange to have this method called
diff --git a/tests/test_arbiter.py b/tests/test_arbiter.py
index 5d22473e..5ab6e920 100644
--- a/tests/test_arbiter.py
+++ b/tests/test_arbiter.py
@@ -16,7 +16,7 @@ import gunicorn.arbiter
 
 class DummyApplication(gunicorn.app.base.BaseApplication):
     """
-    Dummy application that has an default configuration.
+    Dummy application that has a default configuration.
     """
 
     def init(self, parser, opts, args):
@@ -114,6 +114,34 @@ def test_arbiter_reexec_limit_child(fork):
     assert fork.called is False, "should not fork when arbiter is a child"
 
 
+@mock.patch('os.fork')
+def test_arbiter_calls_worker_exit(mock_os_fork):
+    mock_os_fork.return_value = 0
+
+    arbiter = gunicorn.arbiter.Arbiter(DummyApplication())
+    arbiter.cfg.settings['worker_exit'] = mock.Mock()
+    arbiter.pid = None
+    mock_worker = mock.Mock()
+    arbiter.worker_class = mock.Mock(return_value=mock_worker)
+    try:
+        arbiter.spawn_worker()
+    except SystemExit:
+        pass
+    arbiter.cfg.worker_exit.assert_called_with(arbiter, mock_worker)
+
+
+@mock.patch('os.waitpid')
+def test_arbiter_reap_workers(mock_os_waitpid):
+    mock_os_waitpid.side_effect = [(42, 0), (0, 0)]
+    arbiter = gunicorn.arbiter.Arbiter(DummyApplication())
+    arbiter.cfg.settings['child_exit'] = mock.Mock()
+    mock_worker = mock.Mock()
+    arbiter.WORKERS = {42: mock_worker}
+    arbiter.reap_workers()
+    mock_worker.tmp.close.assert_called_with()
+    arbiter.cfg.child_exit.assert_called_with(arbiter, mock_worker)
+
+
 class PreloadedAppWithEnvSettings(DummyApplication):
     """
     Simple application that makes use of the 'preload' feature to