diff --git a/include/boost/numeric/ublas/traits.hpp b/include/boost/numeric/ublas/traits.hpp
index 86ae9b5..f1f6580 100644
--- a/include/boost/numeric/ublas/traits.hpp
+++ b/include/boost/numeric/ublas/traits.hpp
@@ -30,6 +30,10 @@
 #include <boost/type_traits/is_unsigned.hpp>
 #include <boost/mpl/and.hpp>
 
+#ifdef BOOST_UBLAS_USE_INTERVAL
+#include <boost/numeric/interval.hpp>
+#endif
+
 // anonymous namespace to avoid ADL issues
 namespace {
   template<class T> T boost_numeric_ublas_sqrt (const T& t) {