diff --git a/system/graph/TupleGraph.cpp b/system/graph/TupleGraph.cpp
index b94316696..4c2f1cf08 100644
--- a/system/graph/TupleGraph.cpp
+++ b/system/graph/TupleGraph.cpp
@@ -292,7 +292,7 @@ TupleGraph TupleGraph::load_tsv( std::string path ) {
 }
 
 /// Matrix Market format loader
-TupleGraph TupleGraph::load_mm( std::string path ) {
+TupleGraph TupleGraph::load_mm( std::string path, bool one_indexed ) {
   // make sure file exists
   CHECK( fs::exists( path ) ) << "File not found.";
   CHECK( fs::is_regular_file( path ) ) << "File is not a regular file.";
@@ -442,8 +442,10 @@ TupleGraph TupleGraph::load_mm( std::string path ) {
           std::getline( infile, str );
         } else {
           infile >> v0;
+          if(one_indexed) v0--;
           if( !infile.good() ) break;
           infile >> v1;
+          if(one_indexed) v1--;
           if( header_info.field_double ) {
             double d;
             infile >> d;
diff --git a/system/graph/TupleGraph.hpp b/system/graph/TupleGraph.hpp
index 4793cc4bf..8d10965dd 100644
--- a/system/graph/TupleGraph.hpp
+++ b/system/graph/TupleGraph.hpp
@@ -53,7 +53,7 @@ namespace Grappa {
     void save_generic( std::string, void (*f)( const char *, Edge*, Edge*) );
     
     static TupleGraph load_tsv( std::string path );
-    static TupleGraph load_mm( std::string path );
+    static TupleGraph load_mm( std::string path, bool one_indexed = true );
     
   public:
     GlobalAddress<Edge> edges;