diff --git a/Eigen/src/Geometry/Quaternion.h b/Eigen/src/Geometry/Quaternion.h
index dd1217e5e..bebfca422 100644
--- a/Eigen/src/Geometry/Quaternion.h
+++ b/Eigen/src/Geometry/Quaternion.h
@@ -197,20 +197,25 @@ class QuaternionBase : public RotationBase<Derived, 3>
   #else
 
   template<typename NewScalarType>
-  EIGEN_DEVICE_FUNC inline 
+  EIGEN_DEVICE_FUNC inline
   typename internal::enable_if<internal::is_same<Scalar,NewScalarType>::value,const Derived&>::type cast() const
   {
     return derived();
   }
 
   template<typename NewScalarType>
-  EIGEN_DEVICE_FUNC inline 
+  EIGEN_DEVICE_FUNC inline
   typename internal::enable_if<!internal::is_same<Scalar,NewScalarType>::value,Quaternion<NewScalarType> >::type cast() const
   {
     return Quaternion<NewScalarType>(coeffs().template cast<NewScalarType>());
   }
   #endif
 
+  friend std::ostream& operator<<(std::ostream& s, const QuaternionBase<Derived>& q) {
+    s << q.x() << "i + " << q.y() << "j + " << q.z() << "k" << " + " << q.w();
+    return s;
+  }
+
 #ifdef EIGEN_QUATERNIONBASE_PLUGIN
 # include EIGEN_QUATERNIONBASE_PLUGIN
 #endif
diff --git a/test/geo_quaternion.cpp b/test/geo_quaternion.cpp
index 1da683c0e..b339a5f39 100644
--- a/test/geo_quaternion.cpp
+++ b/test/geo_quaternion.cpp
@@ -75,6 +75,11 @@ template<typename Scalar, int Options> void quaternion(void)
   q1.coeffs().setRandom();
   VERIFY_IS_APPROX(q1.coeffs(), (q1*q2).coeffs());
 
+  // Printing
+  std::ostringstream ss;
+  ss << q2;
+  VERIFY(ss.str() == "0i + 0j + 0k + 1");
+  
   // concatenation
   q1 *= q2;