diff --git a/src/classes/ExtendedGraph.class.php b/src/classes/ExtendedGraph.class.php
index 22779539..46a967da 100644
--- a/src/classes/ExtendedGraph.class.php
+++ b/src/classes/ExtendedGraph.class.php
@@ -141,7 +141,7 @@ public function make_resource_array($resource) {
      * @return boolean true if the triple was new, false if it already existed in the graph
      */
     public function add_resource_triple($s, $p, $o) {
-        if($this->isValidResourceValue($o)) {
+        if($this->isValidTripleValue($s) && $this->isValidTripleValue($p) && $this->isValidTripleValue($o)) {
             return $this->_add_triple($s, $p, array('type' => strpos($o, '_:') === 0 ? 'bnode' : 'uri', 'value' => $o));
         }
         return false;
@@ -157,7 +157,7 @@ public function add_resource_triple($s, $p, $o) {
      * @return boolean true if the triple was new, false if it already existed in the graph
      */
     public function add_literal_triple($s, $p, $o, $lang = null, $dt = null) {
-        if($this->isValidLiteralValue($o)) {
+        if($this->isValidTripleValue($s) && $this->isValidTripleValue($p) && $this->isValidLiteralValue($o)) {
             $o_info = array('type' => 'literal', 'value' => $o);
             if ($lang != null) {
                 $o_info['lang'] = $lang;
@@ -177,17 +177,22 @@ public function add_literal_triple($s, $p, $o, $lang = null, $dt = null) {
      * @return bool
      */
     private function _add_triple($s, $p, Array $o_info) {
-        if (!isset($this->_index[$s])) {
-            $this->_index[$s] = array();
-            $this->_index[$s][$p] = array($o_info);
-            return true;
-        } elseif (!isset($this->_index[$s][$p])) {
-            $this->_index[$s][$p] = array($o_info);
-            return true;
-        } else {
-            if (!in_array($o_info, $this->_index[$s][$p])) {
-                $this->_index[$s][$p][] = $o_info;
+        // The value $o should already have been validated by this point
+        // It's validation differs depending on whether it is a literal or resource
+        // So just check the subject and predicate here...
+        if($this->isValidTripleValue($s) && $this->isValidTripleValue($p)) {
+            if (!isset($this->_index[$s])) {
+                $this->_index[$s] = array();
+                $this->_index[$s][$p] = array($o_info);
+                return true;
+            } elseif (!isset($this->_index[$s][$p])) {
+                $this->_index[$s][$p] = array($o_info);
                 return true;
+            } else {
+                if (!in_array($o_info, $this->_index[$s][$p])) {
+                    $this->_index[$s][$p][] = $o_info;
+                    return true;
+                }
             }
         }
         return false;
@@ -215,7 +220,7 @@ protected function isValidLiteralValue($value){
      *
      * @return bool
      */
-    protected function isValidResourceValue($value){
+    protected function isValidTripleValue($value){
         if(!is_string($value)){
             return false;
         }
diff --git a/src/mongo/MongoGraph.class.php b/src/mongo/MongoGraph.class.php
index 1a5c319e..ead47088 100644
--- a/src/mongo/MongoGraph.class.php
+++ b/src/mongo/MongoGraph.class.php
@@ -128,11 +128,20 @@ private function add_tarray_to_index($tarray)
         {
             if($key[0] != '_')
             {
-                $predicate = $this->qname_to_uri($key);
-                $graphValueObject = $this->toGraphValueObject($value);
-                // Only add if valid values have been found
-                if($graphValueObject !== false) {
-                    $predObjects[$predicate] = $graphValueObject;
+                // Make sure the predicate is valid
+                if($this->isValidTripleValue($key)){
+                    $predicate = $this->qname_to_uri($key);
+                    $graphValueObject = $this->toGraphValueObject($value);
+                    // Only add if valid values have been found
+                    if ($graphValueObject !== false) {
+                        $predObjects[$predicate] = $graphValueObject;
+                    }
+                }
+            }
+            else if($key == "_id"){
+                // If the subject is not valid then return
+                if(!isset($value['r']) || !$this->isValidTripleValue($value['r'])){
+                    return;
                 }
             }
         }
@@ -163,7 +172,7 @@ private function toGraphValueObject($mongoValueObject)
         else if (array_key_exists(VALUE_URI,$mongoValueObject))
         {
             // only allow valid values
-            if($this->isValidResourceValue($mongoValueObject[VALUE_URI])) {
+            if($this->isValidTripleValue($mongoValueObject[VALUE_URI])) {
                 // single value uri
                 $simpleGraphValueObject[] = array(
                     'type' => 'uri',
@@ -185,7 +194,7 @@ private function toGraphValueObject($mongoValueObject)
                         $valueTypeLabel = 'literal';
                     }
                     else{
-                        if(!$this->isValidResourceValue($value)){
+                        if(!$this->isValidTripleValue($value)){
                             continue;
                         }
                         $valueTypeLabel = 'uri';
diff --git a/test/unit/ExtendedGraphTest.php b/test/unit/ExtendedGraphTest.php
index 500d9e83..41134376 100644
--- a/test/unit/ExtendedGraphTest.php
+++ b/test/unit/ExtendedGraphTest.php
@@ -64,6 +64,56 @@ public function addInvalidValueToLiteralResultsInNoTriple_Provider(){
         );
     }
 
+    /**
+     * @dataProvider addInvalidSubjectToLiteralResultsInNoTriple_Provider
+     */
+    public function testAddInvalidSubjectToLiteralResultsInNoTriple($value)
+    {
+        $graph = new ExtendedGraph();
+
+        $addResult = $graph->add_resource_triple($value, 'http://some/predicate', 'http://someplace.com');
+        $this->assertFalse($addResult, 'The triple should not have been added for this value');
+
+        $graph->get_triple_count();
+        $this->assertEquals(0, $graph->get_triple_count(), 'The triple should not have been added for this value');
+    }
+    public function addInvalidSubjectToLiteralResultsInNoTriple_Provider(){
+        return array(
+            array(1),
+            array(1.2),
+            array(true),
+            array(array()),
+            array(null),
+            array(new stdClass()),
+            array(function(){})
+        );
+    }
+
+    /**
+     * @dataProvider addInvalidSubjectToLiteralResultsInNoTriple_Provider
+     */
+    public function testAddInvalidPredicateToLiteralResultsInNoTriple($value)
+    {
+        $graph = new ExtendedGraph();
+
+        $addResult = $graph->add_resource_triple('http://some/subject/1', $value, 'http://someplace.com');
+        $this->assertFalse($addResult, 'The triple should not have been added for this value');
+
+        $graph->get_triple_count();
+        $this->assertEquals(0, $graph->get_triple_count(), 'The triple should not have been added for this value');
+    }
+    public function addInvalidPredicateToLiteralResultsInNoTriple_Provider(){
+        return array(
+            array(1),
+            array(1.2),
+            array(true),
+            array(array()),
+            array(null),
+            array(new stdClass()),
+            array(function(){})
+        );
+    }
+
     public function testAddValidValueToResourceResultsInTriple()
     {
         $value = 'A String';
@@ -101,6 +151,56 @@ public function addInvalidValueToResourceResultsInNoTriple_Provider(){
         );
     }
 
+    /**
+     * @dataProvider addInvalidSubjectToResourceResultsInNoTriple_Provider
+     */
+    public function testAddInvalidSubjectToResourceResultsInNoTriple($value)
+    {
+        $graph = new ExtendedGraph();
+
+        $addResult = $graph->add_resource_triple($value, 'http://some/predicate', 'http://someplace.com');
+        $this->assertFalse($addResult, 'The triple should not have been added for this value');
+
+        $graph->get_triple_count();
+        $this->assertEquals(0, $graph->get_triple_count(), 'The triple should not have been added for this value');
+    }
+    public function addInvalidSubjectToResourceResultsInNoTriple_Provider(){
+        return array(
+            array(1),
+            array(1.2),
+            array(true),
+            array(array()),
+            array(null),
+            array(new stdClass()),
+            array(function(){})
+        );
+    }
+
+    /**
+     * @dataProvider addInvalidSubjectToLiteralResultsInNoTriple_Provider
+     */
+    public function testAddInvalidPredicateToResourceResultsInNoTriple($value)
+    {
+        $graph = new ExtendedGraph();
+
+        $addResult = $graph->add_resource_triple('http://some/subject/1', $value, 'http://someplace.com');
+        $this->assertFalse($addResult, 'The triple should not have been added for this value');
+
+        $graph->get_triple_count();
+        $this->assertEquals(0, $graph->get_triple_count(), 'The triple should not have been added for this value');
+    }
+    public function addInvalidPredicateToResourceResultsInNoTriple_Provider(){
+        return array(
+            array(1),
+            array(1.2),
+            array(true),
+            array(array()),
+            array(null),
+            array(new stdClass()),
+            array(function(){})
+        );
+    }
+
     public function testRemoveProperties()
     {
         $graph = new ExtendedGraph();
diff --git a/test/unit/mongo/MongoGraphTest.php b/test/unit/mongo/MongoGraphTest.php
index 7534baa0..304027b7 100644
--- a/test/unit/mongo/MongoGraphTest.php
+++ b/test/unit/mongo/MongoGraphTest.php
@@ -171,6 +171,64 @@ public function addTripodArrayContainingInvalidLiteralValues_Provider(){
         );
     }
 
+    /**
+     * @dataProvider addTripodArrayContainingInvalidPredicates_Provider
+     */
+    public function testAddTripodArrayContainingInvalidPredicates($value)
+    {
+        $doc = array(
+            "_id"=>array("r"=>"http://talisaspire.com/works/4d101f63c10a6-2", "c"=>"http://talisaspire.com/works/4d101f63c10a6-2"),
+            "_version"=>0,
+            "rdf:type"=>array(
+                array("l"=>"a Value"),
+            ),
+            "bibo:isbn13"=>array("l"=>"9211234567890"),
+            $value=>array("l"=>"9211234567890")
+        );
+
+        $expected = new \Tripod\Mongo\MongoGraph();
+        $expected->add_literal_triple("http://talisaspire.com/works/4d101f63c10a6-2", $expected->qname_to_uri("bibo:isbn13"),"9211234567890");
+        $expected->add_literal_triple("http://talisaspire.com/works/4d101f63c10a6-2", $expected->qname_to_uri("rdf:type"),"a Value");
+
+        $g = new \Tripod\Mongo\MongoGraph();
+        $g->add_tripod_array($doc);
+
+        $this->assertEquals($expected, $g);
+    }
+    public function addTripodArrayContainingInvalidPredicates_Provider(){
+        return array(
+            array(1),
+            array(1.2),
+            array(true),
+        );
+    }
+
+    /**
+     * @dataProvider addTripodArrayContainingInvalidSubject_Provider
+     */
+    public function testAddTripodArrayContainingInvalidSubject($value)
+    {
+        $doc = array(
+            "_id"=>array("r"=>$value, "c"=>"http://talisaspire.com/works/4d101f63c10a6-2"),
+            "_version"=>0,
+            "rdf:type"=>array(
+                array("l"=>"a Value"),
+            ),
+            "bibo:isbn13"=>array("l"=>"9211234567890"),
+        );
+
+        $g = new \Tripod\Mongo\MongoGraph();
+        $g->add_tripod_array($doc);
+        $this->assertEquals(0, $g->get_triple_count());
+    }
+    public function addTripodArrayContainingInvalidSubject_Provider(){
+        return array(
+            array(1),
+            array(1.2),
+            array(true),
+        );
+    }
+
 
     public function testAddTripodArrayContainingValidResourceValues()
     {