diff --git a/var/spack/repos/builtin/packages/charmpp/package.py b/var/spack/repos/builtin/packages/charmpp/package.py
index 35d1e7b9505..6d8bda0f372 100644
--- a/var/spack/repos/builtin/packages/charmpp/package.py
+++ b/var/spack/repos/builtin/packages/charmpp/package.py
@@ -370,10 +370,11 @@ def check_build(self):
              'test', 'TESTOPTS=++local', parallel=False)
 
     def setup_dependent_build_environment(self, env, dependent_spec):
-        env.set('MPICC',  self.prefix.bin.ampicc)
-        env.set('MPICXX', self.prefix.bin.ampicxx)
-        env.set('MPIF77', self.prefix.bin.ampif77)
-        env.set('MPIF90', self.prefix.bin.ampif90)
+        if not self.spec.satisfies("backend=mpi"):
+            env.set('MPICC',  self.prefix.bin.ampicc)
+            env.set('MPICXX', self.prefix.bin.ampicxx)
+            env.set('MPIF77', self.prefix.bin.ampif77)
+            env.set('MPIF90', self.prefix.bin.ampif90)
 
     def setup_dependent_package(self, module, dependent_spec):
         self.spec.mpicc     = self.prefix.bin.ampicc