diff --git a/src/epoll.cpp b/src/epoll.cpp
index 1b726885..ab792164 100644
--- a/src/epoll.cpp
+++ b/src/epoll.cpp
@@ -92,7 +92,9 @@ void zmq::epoll_t::rm_fd (handle_t handle_)
     int rc = epoll_ctl (epoll_fd, EPOLL_CTL_DEL, pe->fd, &pe->ev);
     errno_assert (rc != -1);
     pe->fd = retired_fd;
+    retired_sync.lock ();
     retired.push_back (pe);
+    retired_sync.unlock ();
 
     //  Decrease the load metric of the thread.
     adjust_load (-1);
@@ -180,10 +182,12 @@ void zmq::epoll_t::loop ()
         }
 
         //  Destroy retired event sources.
+        retired_sync.lock ();
         for (retired_t::iterator it = retired.begin (); it != retired.end (); ++it) {
             LIBZMQ_DELETE(*it);
         }
         retired.clear ();
+        retired_sync.unlock ();
     }
 }
 
diff --git a/src/epoll.hpp b/src/epoll.hpp
index 567a4bf3..6c2f9219 100644
--- a/src/epoll.hpp
+++ b/src/epoll.hpp
@@ -41,6 +41,7 @@
 #include "fd.hpp"
 #include "thread.hpp"
 #include "poller_base.hpp"
+#include "mutex.h"
 
 namespace zmq
 {
@@ -102,6 +103,9 @@ namespace zmq
         //  Handle of the physical thread doing the I/O work.
         thread_t worker;
 
+        // Synchronisation of the retired event source
+        mutex_t retired_sync;
+
         epoll_t (const epoll_t&);
         const epoll_t &operator = (const epoll_t&);
     };