diff --git a/lib/spack/spack/build_systems/cmake.py b/lib/spack/spack/build_systems/cmake.py
index ca9ec6f803c..13d12d97ebb 100644
--- a/lib/spack/spack/build_systems/cmake.py
+++ b/lib/spack/spack/build_systems/cmake.py
@@ -144,7 +144,7 @@ def _std_args(pkg):
 
         # Set up CMake rpath
         args.append('-DCMAKE_INSTALL_RPATH_USE_LINK_PATH:BOOL=FALSE')
-        rpaths = ':'.join(spack.build_environment.get_rpaths(pkg))
+        rpaths = ';'.join(spack.build_environment.get_rpaths(pkg))
         args.append('-DCMAKE_INSTALL_RPATH:STRING={0}'.format(rpaths))
         # CMake's find_package() looks in CMAKE_PREFIX_PATH first, help CMake
         # to find immediate link dependencies in right places: