diff --git a/src/JsonSchema/Constraints/ObjectConstraint.php b/src/JsonSchema/Constraints/ObjectConstraint.php
index 0e5cf1b9..58ce5c9f 100644
--- a/src/JsonSchema/Constraints/ObjectConstraint.php
+++ b/src/JsonSchema/Constraints/ObjectConstraint.php
@@ -79,11 +79,14 @@ public function validatePatternProperties($element, $path, $patternProperties)
      */
     public function validateElement($element, $matches, $objectDefinition = null, $path = null, $additionalProp = null)
     {
+        $this->validateMinMaxConstraint($element, $objectDefinition, $path);
         foreach ($element as $i => $value) {
 
             $property = $this->getProperty($element, $i, new UndefinedConstraint());
             $definition = $this->getProperty($objectDefinition, $i);
 
+            $this->validateMinMaxConstraint(!($property instanceof UndefinedConstraint) ? $property : $element, $definition, $path);
+
             // no additional properties allowed
             if (!in_array($i, $matches) && $additionalProp === false && $this->inlineSchemaProperty !== $i && !$definition) {
                 $this->addError($path, "The property " . $i . " is not defined and the definition does not allow additional properties", 'additionalProp');
@@ -146,4 +149,26 @@ protected function getProperty($element, $property, $fallback = null)
 
         return $fallback;
     }
+
+    /**
+     * validating minimum and maximum property constraints (if present) against an element
+     *
+     * @param \stdClass $element          Element to validate
+     * @param \stdClass $objectDefinition ObjectConstraint definition
+     * @param string    $path             Path to test?
+     */
+    protected function validateMinMaxConstraint($element, $objectDefinition, $path) {
+        // Verify minimum number of properties
+        if (isset($objectDefinition->minProperties)) {
+            if (count(get_object_vars($element)) < $objectDefinition->minProperties) {
+                $this->addError($path, "Must contain a minimum of " . $objectDefinition->minProperties . " properties", 'minProperties', array('minProperties' => $objectDefinition->minProperties,));
+            }
+        }
+        // Verify maximum number of properties
+        if (isset($objectDefinition->maxProperties)) {
+            if (count(get_object_vars($element)) > $objectDefinition->maxProperties) {
+                $this->addError($path, "Must contain no more than " . $objectDefinition->maxProperties . " properties", 'maxProperties', array('maxProperties' => $objectDefinition->maxProperties,));
+            }
+        }
+    }
 }
diff --git a/src/JsonSchema/Constraints/UndefinedConstraint.php b/src/JsonSchema/Constraints/UndefinedConstraint.php
index c0337200..c90cccf4 100644
--- a/src/JsonSchema/Constraints/UndefinedConstraint.php
+++ b/src/JsonSchema/Constraints/UndefinedConstraint.php
@@ -25,17 +25,10 @@ class UndefinedConstraint extends Constraint
      */
     public function check($value, $schema = null, $path = null, $i = null)
     {
-        if (is_null($schema)) {
+        if (is_null($schema) || !is_object($schema)) {
             return;
         }
 
-        if (!is_object($schema)) {
-            throw new InvalidArgumentException(
-                'Given schema must be an object in ' . $path
-                . ' but is a ' . gettype($schema)
-            );
-        }
-
         $i = is_null($i) ? "" : $i;
         $path = $this->incrementPath($path, $i);
 
@@ -65,10 +58,10 @@ public function validateTypes($value, $schema = null, $path = null, $i = null)
         }
 
         // check object
-        if (is_object($value) && (isset($schema->properties) || isset($schema->patternProperties) || isset($schema->additionalProperties))) {
+        if (is_object($value)) {
             $this->checkObject(
                 $value,
-                isset($schema->properties) ? $schema->properties : null,
+                isset($schema->properties) ? $schema->properties : $schema,
                 $path,
                 isset($schema->additionalProperties) ? $schema->additionalProperties : null,
                 isset($schema->patternProperties) ? $schema->patternProperties : null
@@ -165,20 +158,6 @@ protected function validateCommonProperties($value, $schema = null, $path = null
             }
         }
 
-        // Verify minimum and maximum number of properties
-        if (is_object($value)) {
-            if (isset($schema->minProperties)) {
-                if (count(get_object_vars($value)) < $schema->minProperties) {
-                    $this->addError($path, "Must contain a minimum of " . $schema->minProperties . " properties", 'minProperties', array('minProperties' => $schema->minProperties,));
-                }
-            }
-            if (isset($schema->maxProperties)) {
-                if (count(get_object_vars($value)) > $schema->maxProperties) {
-                    $this->addError($path, "Must contain no more than " . $schema->maxProperties . " properties", 'maxProperties', array('maxProperties' => $schema->maxProperties,));
-                }
-            }
-        }
-
         // Verify that dependencies are met
         if (is_object($value) && isset($schema->dependencies)) {
             $this->validateDependencies($value, $schema->dependencies, $path);