diff --git a/gtsam/nonlinear/Values.h b/gtsam/nonlinear/Values.h
index 5a8005db4..9833a1a86 100644
--- a/gtsam/nonlinear/Values.h
+++ b/gtsam/nonlinear/Values.h
@@ -151,11 +151,22 @@ namespace gtsam {
       typedef _KeyValuePair<ValueType> KeyValuePair;
 
     private:
-      typedef boost::transformed_range<
-          KeyValuePair(*)(Values::KeyValuePair key_value),
-          const boost::filtered_range<
-          boost::function<bool(const Values::ConstKeyValuePair&)>,
-          const boost::iterator_range<iterator> > > Base;
+    	typedef boost::transformed_range<
+    			KeyValuePair(*)(Values::KeyValuePair key_value),
+    			const boost::filtered_range<
+    			boost::function<bool(const Values::ConstKeyValuePair&)>,
+    			const boost::iterator_range<iterator> > > Base;
+    public:
+      /** Returns the number of values in this view */
+      size_t size() const {
+      	typename Base::iterator it = this->begin();
+      	size_t i = 0;
+      	for (; it!=this->end(); ++it)
+      		++i;
+      	return i;
+      }
+
+    private:
 
       Filtered(const Base& base) : Base(base) {}
 
@@ -178,6 +189,18 @@ namespace gtsam {
           boost::function<bool(const Values::ConstKeyValuePair&)>,
           const boost::iterator_range<const_iterator> > > Base;
 
+    public:
+      /** Returns the number of values in this view */
+      size_t size() const {
+      	typename Base::const_iterator it = this->begin();
+      	size_t i = 0;
+      	for (; it!=this->end(); ++it)
+      		++i;
+      	return i;
+      }
+
+    private:
+
       ConstFiltered(const Base& base) : Base(base) {}
 
       friend class Values;
diff --git a/gtsam/nonlinear/tests/testValues.cpp b/gtsam/nonlinear/tests/testValues.cpp
index 064e22e58..5f98e94a0 100644
--- a/gtsam/nonlinear/tests/testValues.cpp
+++ b/gtsam/nonlinear/tests/testValues.cpp
@@ -274,6 +274,7 @@ TEST(Values, filter) {
   // Filter by key
   int i = 0;
   Values::Filtered<Value> filtered = values.filter(boost::bind(std::greater_equal<Key>(), _1, 2));
+  EXPECT_LONGS_EQUAL(2, filtered.size());
   BOOST_FOREACH(const Values::Filtered<>::KeyValuePair& key_value, filtered) {
     if(i == 0) {
       LONGS_EQUAL(2, key_value.key);
@@ -300,6 +301,7 @@ TEST(Values, filter) {
   // Filter by type
   i = 0;
   Values::Filtered<Pose3> pose_filtered = values.filter<Pose3>();
+  EXPECT_LONGS_EQUAL(2, pose_filtered.size());
   BOOST_FOREACH(const Values::Filtered<Pose3>::KeyValuePair& key_value, pose_filtered) {
     if(i == 0) {
     	EXPECT_LONGS_EQUAL(1, key_value.key);