diff --git a/include/boost/preprocessor/seq/size.hpp b/include/boost/preprocessor/seq/size.hpp
index c525fda..2f7b70e 100644
--- a/include/boost/preprocessor/seq/size.hpp
+++ b/include/boost/preprocessor/seq/size.hpp
@@ -23,6 +23,8 @@
 # elif BOOST_PP_CONFIG_FLAGS() & BOOST_PP_CONFIG_EDG() || BOOST_PP_CONFIG_FLAGS() & BOOST_PP_CONFIG_MSVC()
 #    define BOOST_PP_SEQ_SIZE(seq) BOOST_PP_SEQ_SIZE_I(seq)
 #    define BOOST_PP_SEQ_SIZE_I(seq) BOOST_PP_CAT(BOOST_PP_SEQ_SIZE_, BOOST_PP_SEQ_SIZE_0 seq)
+# elif defined(__IBMC__) || defined(__IBMCPP__)
+#    define BOOST_PP_SEQ_SIZE(seq) BOOST_PP_CAT(BOOST_PP_SEQ_SIZE_, BOOST_PP_CAT(BOOST_PP_SEQ_SIZE_0, seq))
 # else
 #    define BOOST_PP_SEQ_SIZE(seq) BOOST_PP_CAT(BOOST_PP_SEQ_SIZE_, BOOST_PP_SEQ_SIZE_0 seq)
 # endif