diff --git a/modules/io/src/CMakeLists.txt b/modules/io/src/CMakeLists.txt
index 0a4917a3cd98e9b4ea3602451b53b3b28c26205f..fcf8da5fd690503cdc3633967a99b9bf40b43b7e 100644
--- a/modules/io/src/CMakeLists.txt
+++ b/modules/io/src/CMakeLists.txt
@@ -166,3 +166,6 @@ target_link_libraries(ost_io ${BOOST_IOSTREAM_LIBRARIES})
 if (ENABLE_IMG)
   target_link_libraries(ost_io ${TIFF_LIBRARIES} ${PNG_LIBRARIES})
 endif()
+
+# Extend the include path for building OST to have msgpack available.
+include_directories("${STAGE_DIR}/include/ost/io/msgpack")
\ No newline at end of file
diff --git a/modules/io/tests/test_io_msgpack.cc b/modules/io/tests/test_io_msgpack.cc
index 586d9eae1f6c9079f4b41894eeda69973f2b05d5..60503c4dd9eeb2444b132777c1d27517ecf60751 100644
--- a/modules/io/tests/test_io_msgpack.cc
+++ b/modules/io/tests/test_io_msgpack.cc
@@ -20,4 +20,4 @@
 // the idea of this test is basically to check that we MessagePack is available
 // to OST. Real testing of MessagePack should happen in that project itself.
 
-//#include <ost/io/msgpack/msgpack.hpp>
+#include <ost/io/msgpack/msgpack.hpp>