diff --git a/src/OpenMesh/Core/IO/writer/STLWriter.cc b/src/OpenMesh/Core/IO/writer/STLWriter.cc
index 8296dd0a..b560d05e 100644
--- a/src/OpenMesh/Core/IO/writer/STLWriter.cc
+++ b/src/OpenMesh/Core/IO/writer/STLWriter.cc
@@ -188,7 +188,7 @@ write_stla(const std::string& _filename, BaseExporter& _be, Options /* _opt */)
     fprintf(out, "\nendloop\nendfacet\n");
   }
 
-
+  fprintf(out, "endsolid\n");
 
   fclose(out);
 
@@ -243,6 +243,8 @@ write_stla(std::ostream& _out, BaseExporter& _be, Options /* _opt */, std::strea
     _out << "\nendloop\nendfacet\n";
   }
 
+  _out << "endsolid\n";
+
   return true;
 }