diff --git a/src/sc_mpi.c b/src/sc_mpi.c
index 393a7481..249902cb 100644
--- a/src/sc_mpi.c
+++ b/src/sc_mpi.c
@@ -757,7 +757,7 @@ sc_mpi_sizeof (sc_MPI_Datatype t)
     return sizeof (int);
   if (t == sc_MPI_LONG || t == sc_MPI_UNSIGNED_LONG)
     return sizeof (long);
-  if (t == sc_MPI_LONG_LONG_INT || t == sc_MPI_UNSIGNED_LONG_LONG)
+  if (t == sc_MPI_LONG_LONG_INT)
     return sizeof (long long);
   if (t == sc_MPI_FLOAT)
     return sizeof (float);
diff --git a/src/sc_mpi.h b/src/sc_mpi.h
index ad6eef31..73d31f81 100644
--- a/src/sc_mpi.h
+++ b/src/sc_mpi.h
@@ -196,7 +196,6 @@ sc_MPI_IO_Errorcode_t;
 #define sc_MPI_LONG                MPI_LONG
 #define sc_MPI_UNSIGNED_LONG       MPI_UNSIGNED_LONG
 #define sc_MPI_LONG_LONG_INT       MPI_LONG_LONG_INT
-#define sc_MPI_UNSIGNED_LONG_LONG  MPI_LONG_LONG_INT
 #define sc_MPI_FLOAT               MPI_FLOAT
 #define sc_MPI_DOUBLE              MPI_DOUBLE
 #define sc_MPI_LONG_DOUBLE         MPI_LONG_DOUBLE
@@ -366,7 +365,6 @@ sc_MPI_IO_Errorcode_t;
 #define sc_MPI_LONG                SC3_MPI_LONG
 #define sc_MPI_UNSIGNED_LONG       ((sc_MPI_Datatype) 0x4c000408)
 #define sc_MPI_LONG_LONG_INT       SC3_MPI_LONG_LONG
-#define sc_MPI_UNSIGNED_LONG_LONG  ((sc_MPI_Datatype) 0x4c000409)
 #define sc_MPI_FLOAT               SC3_MPI_FLOAT
 #define sc_MPI_DOUBLE              SC3_MPI_DOUBLE
 #define sc_MPI_LONG_DOUBLE         ((sc_MPI_Datatype) 0x4c000c0c)