diff --git a/gtsam/inference/VariableIndex.cpp b/gtsam/inference/VariableIndex.cpp
index 26ba191dd..8ce667664 100644
--- a/gtsam/inference/VariableIndex.cpp
+++ b/gtsam/inference/VariableIndex.cpp
@@ -30,11 +30,11 @@ bool VariableIndex::equals(const VariableIndex& other, double tol) const {
 }
 
 /* ************************************************************************* */
-void VariableIndex::print(const string& str) const {
+void VariableIndex::print(const string& str, const KeyFormatter& keyFormatter) const {
   cout << str;
   cout << "nEntries = " << nEntries() << ", nFactors = " << nFactors() << "\n";
   BOOST_FOREACH(KeyMap::value_type key_factors, index_) {
-    cout << "var " << key_factors.first << ":";
+    cout << "var " << keyFormatter(key_factors.first) << ":";
     BOOST_FOREACH(const size_t factor, key_factors.second)
       cout << " " << factor;
     cout << "\n";
diff --git a/gtsam/inference/VariableIndex.h b/gtsam/inference/VariableIndex.h
index 14fbc2072..ed7aaae55 100644
--- a/gtsam/inference/VariableIndex.h
+++ b/gtsam/inference/VariableIndex.h
@@ -106,7 +106,8 @@ public:
   bool equals(const VariableIndex& other, double tol=0.0) const;
 
   /** Print the variable index (for unit tests and debugging). */
-  void print(const std::string& str = "VariableIndex: ") const;
+  void print(const std::string& str = "VariableIndex: ",
+      const KeyFormatter& keyFormatter = DefaultKeyFormatter) const;
 
   /**
    * Output dual hypergraph to Metis file format for use with hmetis