diff --git a/IlmBase/IlmThread/Makefile.am b/IlmBase/IlmThread/Makefile.am
index dde24e48a9..88aaec2362 100644
--- a/IlmBase/IlmThread/Makefile.am
+++ b/IlmBase/IlmThread/Makefile.am
@@ -14,7 +14,7 @@ libIlmThread_la_LDFLAGS = -version-info @LIBTOOL_VERSION@ -no-undefined
 if LIB_SUFFIX_EXISTS
 libIlmThread_la_LDFLAGS += -release @LIB_SUFFIX@
 endif
-libIlmThread_la_LIBADD = ../Iex/libIex.la
+libIlmThread_la_LIBADD = ../Iex/libIex.la $(PTHREAD_LIBS)
 
 libIlmThreadincludedir = $(includedir)/OpenEXR