diff --git a/build/script/runtests.sh b/build/script/runtests.sh
index c5fd939a8..501a2340b 100755
--- a/build/script/runtests.sh
+++ b/build/script/runtests.sh
@@ -18,6 +18,14 @@ components=`cat $POCO_BASE/components`
 
 if [ "$OSNAME" = "" ] ; then
 	OSNAME=`uname`
+        case $OSNAME in
+        CYGWIN*)
+                OSNAME=CYGWIN 
+                TESTRUNNER=$TESTRUNNER.exe
+                ;;
+        MINGW*)
+                OSNAME=MinGW ;;
+        esac
 fi
 if [ "$OSARCH" = "" ] ; then
 	OSARCH=`uname -m | tr ' /' _-`