diff --git a/var/spack/repos/builtin/packages/mumps/package.py b/var/spack/repos/builtin/packages/mumps/package.py
index 82d0c606b6..1d87d6f35a 100644
--- a/var/spack/repos/builtin/packages/mumps/package.py
+++ b/var/spack/repos/builtin/packages/mumps/package.py
@@ -81,7 +81,7 @@ def write_makefile_inc(self):
 
         lapack_blas = (self.spec['lapack'].lapack_libs +
                        self.spec['blas'].blas_libs)
-        makefile_conf = ["LIBBLAS = %s" % lapack_blas.joined()]
+        makefile_conf = ["LIBBLAS = %s" % lapack_blas.ld_flags]
 
         orderings = ['-Dpord']