diff --git a/gtsam/navigation/ImuBias.h b/gtsam/navigation/ImuBias.h
index 1a63691bf..929b7ac22 100644
--- a/gtsam/navigation/ImuBias.h
+++ b/gtsam/navigation/ImuBias.h
@@ -137,7 +137,7 @@ public:
   }
 
   /// print with optional string
-  void print(const std::string& s = "") const { std::cout << s << *this; }
+  void print(const std::string& s = "") const { std::cout << s << *this << std::endl; }
 
   /** equality up to tolerance */
   inline bool equals(const ConstantBias& expected, double tol = 1e-5) const {
diff --git a/gtsam/navigation/ImuFactor.cpp b/gtsam/navigation/ImuFactor.cpp
index a37d74b63..a03dd92f8 100644
--- a/gtsam/navigation/ImuFactor.cpp
+++ b/gtsam/navigation/ImuFactor.cpp
@@ -122,17 +122,22 @@ gtsam::NonlinearFactor::shared_ptr ImuFactor::clone() const {
       gtsam::NonlinearFactor::shared_ptr(new This(*this)));
 }
 
+//------------------------------------------------------------------------------
+std::ostream& operator<<(std::ostream& os, const ImuFactor& f) {
+  os << "  preintegrated measurements:\n" << f._PIM_;
+  ;
+  // Print standard deviations on covariance only
+  os << "  noise model sigmas: " << f.noiseModel_->sigmas().transpose();
+  return os;
+}
+
 //------------------------------------------------------------------------------
 void ImuFactor::print(const string& s, const KeyFormatter& keyFormatter) const {
   cout << s << "ImuFactor(" << keyFormatter(this->key1()) << ","
       << keyFormatter(this->key2()) << "," << keyFormatter(this->key3()) << ","
       << keyFormatter(this->key4()) << "," << keyFormatter(this->key5())
       << ")\n";
-  Base::print("");
-  _PIM_.print("  preintegrated measurements:");
-  // Print standard deviations on covariance only
-  cout << "  noise model sigmas: " << this->noiseModel_->sigmas().transpose()
-      << endl;
+  cout << *this << endl;
 }
 
 //------------------------------------------------------------------------------
diff --git a/gtsam/navigation/ImuFactor.h b/gtsam/navigation/ImuFactor.h
index d94789d4a..b0b37d73b 100644
--- a/gtsam/navigation/ImuFactor.h
+++ b/gtsam/navigation/ImuFactor.h
@@ -201,14 +201,13 @@ public:
   /// @return a deep copy of this factor
   virtual gtsam::NonlinearFactor::shared_ptr clone() const;
 
-  /** implement functions needed for Testable */
-
-  /// print
+  /// @name Testable
+  /// @{
+  GTSAM_EXPORT friend std::ostream& operator<<(std::ostream& os, const ImuFactor&);
   virtual void print(const std::string& s, const KeyFormatter& keyFormatter =
       DefaultKeyFormatter) const;
-
-  /// equals
   virtual bool equals(const NonlinearFactor& expected, double tol = 1e-9) const;
+  /// @}
 
   /** Access the preintegrated measurements. */
 
diff --git a/python/handwritten/navigation/ImuFactor.cpp b/python/handwritten/navigation/ImuFactor.cpp
index 17a497158..d22c93dd9 100644
--- a/python/handwritten/navigation/ImuFactor.cpp
+++ b/python/handwritten/navigation/ImuFactor.cpp
@@ -37,7 +37,7 @@ void exportImuFactor() {
       .def(init<const Vector3&, const Vector3&>())
       .def(repr(self));
 
-  class_<PreintegrationParams, boost::shared_ptr<PreintegrationParams> >(
+  class_<PreintegrationParams, boost::shared_ptr<PreintegrationParams>>(
       "PreintegrationParams", init<const Vector3&>())
       .def_readwrite("gyroscopeCovariance",
                      &PreintegrationParams::gyroscopeCovariance)
@@ -67,5 +67,8 @@ void exportImuFactor() {
       .def("preintMeasCov", &PreintegratedImuMeasurements::preintMeasCov);
 
   // NOTE(frank): Abstract classes need boost::noncopyable
-  class_<ImuFactor, boost::noncopyable>("ImuFactor", no_init);
+  class_<ImuFactor, bases<NonlinearFactor>, boost::shared_ptr<ImuFactor>>(
+      "ImuFactor")
+      .def(init<Key, Key, Key, Key, Key, const PreintegratedImuMeasurements&>())
+      .def(repr(self));
 }