diff --git a/gtsam/nonlinear/ISAM2.h b/gtsam/nonlinear/ISAM2.h
index 30f0b14d2..42c38514c 100644
--- a/gtsam/nonlinear/ISAM2.h
+++ b/gtsam/nonlinear/ISAM2.h
@@ -490,6 +490,9 @@ public:
   /** Access the current ordering */
   const Ordering& getOrdering() const { return ordering_; }
 
+  /** Access the nonlinear variable index */
+  const VariableIndex& getVariableIndex() const { return variableIndex_; }
+
   size_t lastAffectedVariableCount;
   size_t lastAffectedFactorCount;
   size_t lastAffectedCliqueCount;