diff --git a/bitcoin-qt.pro b/bitcoin-qt.pro
index 1929122df..473fb2778 100644
--- a/bitcoin-qt.pro
+++ b/bitcoin-qt.pro
@@ -2,7 +2,7 @@ TEMPLATE = app
 TARGET =
 VERSION = 0.5.0
 INCLUDEPATH += src src/json src/qt
-DEFINES += QT_GUI
+DEFINES += QT_GUI BOOST_THREAD_USE_LIB
 CONFIG += no_include_pwd
 
 # for boost 1.37, add -mt to the boost libraries