diff --git a/Python/thread.c b/Python/thread.c
index 4c0edfb..5e7fc6c 100644
--- a/Python/thread.c
+++ b/Python/thread.c
@@ -45,6 +45,20 @@
 #define SUN_LWP
 #endif
 
+/* Check if we're running on HP-UX and _SC_THREADS is defined. If so, then
+   enough of the Posix threads package is implimented to support python 
+   threads.
+
+   This is valid for HP-UX 11.23 running on an ia64 system. If needed, add
+   a check of __ia64 to verify that we're running on a ia64 system instead
+   of a pa-risc system.
+*/
+#ifdef __hpux
+#ifdef _SC_THREADS
+#define _POSIX_THREADS
+#endif
+#endif
+
 #endif /* _POSIX_THREADS */