diff --git a/docs/latex/wx/timer.tex b/docs/latex/wx/timer.tex
index 7830183b5d..262e8332fc 100644
--- a/docs/latex/wx/timer.tex
+++ b/docs/latex/wx/timer.tex
@@ -20,6 +20,8 @@ In any case, you must start the timer with \helpref{Start}{wxtimerstart}
 after constructing it before it actually starts sending notifications. It can
 be stopped later with \helpref{Stop}{wxtimerstop}.
 
+{\bf NB:} note that timer can only be used from the main thread currently.
+
 \wxheading{Derived from}
 
 \helpref{wxObject}{wxobject}
diff --git a/src/common/timercmn.cpp b/src/common/timercmn.cpp
index 3bf88317e8..4853669d20 100644
--- a/src/common/timercmn.cpp
+++ b/src/common/timercmn.cpp
@@ -36,6 +36,7 @@
 #ifndef WX_PRECOMP
     #include "wx/intl.h"
     #include "wx/log.h"
+    #include "wx/thread.h"
 #endif
 
 #include "wx/timer.h"
@@ -131,6 +132,13 @@ void wxTimerBase::Notify()
 
 bool wxTimerBase::Start(int milliseconds, bool oneShot)
 {
+    // under MSW timers only work when they're started from the main thread so
+    // let the caller know about it
+#ifdef wxUSE_THREADS
+    wxASSERT_MSG( wxThread::IsMain(),
+                  _T("timer can only be started from the main thread") );
+#endif // wxUSE_THREADS
+
     if ( IsRunning() )
     {
         // not stopping the already running timer might work for some