diff --git a/jerry-core/ecma/builtin-objects/ecma-builtin-object-prototype.cpp b/jerry-core/ecma/builtin-objects/ecma-builtin-object-prototype.cpp
index cd304e304..ed66fe449 100644
--- a/jerry-core/ecma/builtin-objects/ecma-builtin-object-prototype.cpp
+++ b/jerry-core/ecma/builtin-objects/ecma-builtin-object-prototype.cpp
@@ -252,7 +252,37 @@ static ecma_completion_value_t
 ecma_builtin_object_prototype_object_is_prototype_of (ecma_value_t this_arg, /**< this argument */
                                                       ecma_value_t arg) /**< routine's first argument */
 {
-  ECMA_BUILTIN_CP_UNIMPLEMENTED (this_arg, arg);
+  /* 1. Is the argument an object? */
+  if (!ecma_is_value_object (arg))
+  {
+    return ecma_make_simple_completion_value (ECMA_SIMPLE_VALUE_FALSE);
+  }
+
+  ecma_completion_value_t return_value = ecma_make_empty_completion_value ();
+
+  /* 2. ToObject(this) */
+  ECMA_TRY_CATCH (obj_value,
+                  ecma_op_to_object (this_arg),
+                  return_value);
+
+  ecma_object_t *obj_p = ecma_get_object_from_value (obj_value);
+
+  /* 3. Compare prototype to object */
+  ECMA_TRY_CATCH (v_obj_value,
+                  ecma_op_to_object (arg),
+                  return_value);
+
+  ecma_object_t *v_obj_p = ecma_get_object_from_value (v_obj_value);
+
+  bool is_prototype_of = ecma_op_object_is_prototype_of (obj_p, v_obj_p);
+  return_value = ecma_make_simple_completion_value (is_prototype_of
+                                                    ? ECMA_SIMPLE_VALUE_TRUE
+                                                    : ECMA_SIMPLE_VALUE_FALSE);
+  ECMA_FINALIZE (v_obj_value);
+
+  ECMA_FINALIZE (obj_value);
+
+  return return_value;
 } /* ecma_builtin_object_prototype_object_is_prototype_of */
 
 /**
diff --git a/jerry-core/ecma/operations/ecma-objects.cpp b/jerry-core/ecma/operations/ecma-objects.cpp
index 0ee1682ca..b812876c7 100644
--- a/jerry-core/ecma/operations/ecma-objects.cpp
+++ b/jerry-core/ecma/operations/ecma-objects.cpp
@@ -504,6 +504,36 @@ ecma_op_object_has_instance (ecma_object_t *obj_p, /**< the object */
   JERRY_UNREACHABLE ();
 } /* ecma_op_object_has_instance */
 
+
+
+/**
+ * Object's isPrototypeOf operation
+ *
+ * See also:
+ *          ECMA-262 v5, 15.2.4.6; 3
+ *
+ * @return true if the target object is prototype of the base object
+ *         false if the target object is not prototype of the base object
+ */
+bool
+ecma_op_object_is_prototype_of (ecma_object_t *base_p, /** < base object */
+                                ecma_object_t *target_p) /** < target object */
+{
+  do
+  {
+    target_p = ecma_get_object_prototype (target_p);
+    if (target_p == NULL)
+    {
+      return false;
+    }
+    else if (target_p == base_p)
+    {
+      return true;
+    }
+  } while (true);
+} /* ecma_op_object_is_prototype_of */
+
+
 /**
  * @}
  * @}
diff --git a/jerry-core/ecma/operations/ecma-objects.h b/jerry-core/ecma/operations/ecma-objects.h
index 9e7cbd992..08d4b90b2 100644
--- a/jerry-core/ecma/operations/ecma-objects.h
+++ b/jerry-core/ecma/operations/ecma-objects.h
@@ -45,6 +45,8 @@ ecma_op_object_define_own_property (ecma_object_t *obj_p,
                                     bool is_throw);
 extern ecma_completion_value_t ecma_op_object_has_instance (ecma_object_t *obj_p,
                                                             ecma_value_t value);
+extern bool ecma_op_object_is_prototype_of (ecma_object_t *base_p, ecma_object_t *target_p);
+
 /**
  * @}
  * @}
diff --git a/tests/jerry/object_prototype_isprototypeof.js b/tests/jerry/object_prototype_isprototypeof.js
new file mode 100644
index 000000000..979d591c5
--- /dev/null
+++ b/tests/jerry/object_prototype_isprototypeof.js
@@ -0,0 +1,33 @@
+// Copyright 2015 Samsung Electronics Co., Ltd.
+// Copyright 2015 University of Szeged.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+function Function_A() { }
+function Function_B() { }
+Function_B.prototype = new Function_A();
+
+function Function_C() { }
+Function_C.prototype = new Function_B();
+
+function Function_D() { }
+Function_D.prototype = new Function_C();
+
+var d_instance = new Function_D();
+
+assert (Function_A.prototype.isPrototypeOf (d_instance) === true)
+assert (Function_A.prototype.isPrototypeOf (Array) === false)
+
+
+assert (Function_A.prototype.isPrototypeOf.call(0, 0) === false);
+assert (Function_A.prototype.isPrototypeOf.call(Function_A, 0) === false);