diff --git a/cpp/VSLAMFactor.cpp b/cpp/VSLAMFactor.cpp
index 67ed040fa..68e18fb92 100644
--- a/cpp/VSLAMFactor.cpp
+++ b/cpp/VSLAMFactor.cpp
@@ -35,11 +35,10 @@ void VSLAMFactor::print(const std::string& s) const {
 }
 
 /* ************************************************************************* */
-bool VSLAMFactor::equals(const NonlinearFactor<VSLAMConfig>& f, double tol) const {
-  const VSLAMFactor* p = dynamic_cast<const VSLAMFactor*>(&f);
-  if (p == NULL) return false;
-  if (cameraFrameNumber_ != p->cameraFrameNumber_ || landmarkNumber_ != p->landmarkNumber_) return false;
-  if (!equal_with_abs_tol(this->z_,p->z_,tol)) return false;
+  bool VSLAMFactor::equals(const VSLAMFactor& p, double tol) const {
+  if (&p == NULL) return false;
+  if (cameraFrameNumber_ != p.cameraFrameNumber_ || landmarkNumber_ != p.landmarkNumber_) return false;
+  if (!equal_with_abs_tol(this->z_,p.z_,tol)) return false;
   return true;
 }
 
diff --git a/cpp/VSLAMFactor.h b/cpp/VSLAMFactor.h
index b53c48a8e..2c023a388 100644
--- a/cpp/VSLAMFactor.h
+++ b/cpp/VSLAMFactor.h
@@ -9,6 +9,8 @@
 #include "NonlinearFactor.h"
 #include "LinearFactor.h"
 #include "Cal3_S2.h"
+#include "Testable.h"
+
 
 namespace gtsam {
 
@@ -18,7 +20,8 @@ class VSLAMConfig;
  * Non-linear factor for a constraint derived from a 2D measurement,
  * i.e. the main building block for visual SLAM.
  */
-class VSLAMFactor : public NonlinearFactor<VSLAMConfig>
+//class VSLAMFactor : public NonlinearFactor<VSLAMConfig>, Testable<NonlinearFactor<VSLAMConfig> >
+class VSLAMFactor : public NonlinearFactor<VSLAMConfig>, Testable<VSLAMFactor>
 {
  private:
 
@@ -51,7 +54,7 @@ class VSLAMFactor : public NonlinearFactor<VSLAMConfig>
   /**
    * equals
    */
-  bool equals(const NonlinearFactor<VSLAMConfig>&, double tol=1e-9) const;
+  bool equals(const VSLAMFactor&, double tol=1e-9) const;
 
   /**
    * predict the measurement
diff --git a/cpp/testVSLAMFactor.cpp b/cpp/testVSLAMFactor.cpp
index f8b492751..83f111de8 100644
--- a/cpp/testVSLAMFactor.cpp
+++ b/cpp/testVSLAMFactor.cpp
@@ -70,6 +70,21 @@ TEST( VSLAMFactor, error )
   CHECK(assert_equal(expected_config,actual_config,1e-9));
 }
 
+TEST( VSLAMFactor, equals )
+{
+	// Create two identical factors and make sure they're equal
+	Vector z = Vector_(2,323.,240.);
+	double sigma=1.0;
+	int cameraFrameNumber=1, landmarkNumber=1;
+	boost::shared_ptr<VSLAMFactor>
+	  factor1(new VSLAMFactor(z, sigma, cameraFrameNumber, landmarkNumber, K));
+
+	boost::shared_ptr<VSLAMFactor>
+		factor2(new VSLAMFactor(z, sigma, cameraFrameNumber, landmarkNumber, K));
+
+	CHECK(assert_equal(*factor1, *factor2));
+}
+
 /* ************************************************************************* */
 int main() {
 	TestResult tr;