diff --git a/CHANGES b/CHANGES
index 4dbdc58626..f0403ba470 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,5 @@
+1779.	[port]		OSF 5.1: libtool didn't handle -pthread correctly.
+
 1778.   [port]   	HUX 11.11: fix broken IN6ADDR_ANY_INIT and
 			IN6ADDR_LOOPBACK_INIT macros.
 
diff --git a/ltmain.sh b/ltmain.sh
index 47fa4f179f..06fe7c8796 100644
--- a/ltmain.sh
+++ b/ltmain.sh
@@ -1356,7 +1356,18 @@ EOF
 	continue
 	;;
 
-     -mt|-mthreads|-kthread|-Kthread|-pthread|-pthreads|--thread-safe)
+     -mt|-mthreads|-kthread|-Kthread|-pthreads|--thread-safe)
+	deplibs="$deplibs $arg"
+	continue
+	;;
+
+     -pthread)
+        case $host in
+        *-*-osf5.1)
+	   # -pthread is a compiler only option
+           continue
+           ;;
+        esac
 	deplibs="$deplibs $arg"
 	continue
 	;;