diff --git a/src/amdis/linearalgebra/petsc/MatrixNnzStructure.hpp b/src/amdis/linearalgebra/petsc/MatrixNnzStructure.hpp
index 29423da2538722e705112295b194f35058b09016..25327000bb693f424e0257434284905c78a13b32 100644
--- a/src/amdis/linearalgebra/petsc/MatrixNnzStructure.hpp
+++ b/src/amdis/linearalgebra/petsc/MatrixNnzStructure.hpp
@@ -36,7 +36,9 @@ namespace AMDiS
     unsigned long changeIndex_ = 0;
     bool initialized_ = false;
 
+#if HAVE_MPI
     const Mpi::Tag tag_{916821}; //< Communication tag used internally
+#endif
   };
 
 } // end namespace AMDiS