diff --git a/Foundation/include/Poco/HashMap.h b/Foundation/include/Poco/HashMap.h
index 3684c211c2..65cd154430 100644
--- a/Foundation/include/Poco/HashMap.h
+++ b/Foundation/include/Poco/HashMap.h
@@ -180,6 +180,12 @@ class HashMap
 		return _table.find(value);
 	}
 
+	std::size_t count(const KeyType& key) const
+	{
+		ValueType value(key);
+		return _table.find(value) != _table.end() ? 1 : 0;
+	}
+
 	std::pair<Iterator, bool> insert(const PairType& pair)
 	{
 		ValueType value(pair.first, pair.second);
diff --git a/Foundation/testsuite/src/HashMapTest.cpp b/Foundation/testsuite/src/HashMapTest.cpp
index b1a675bfe8..815cf9e8f1 100644
--- a/Foundation/testsuite/src/HashMapTest.cpp
+++ b/Foundation/testsuite/src/HashMapTest.cpp
@@ -70,6 +70,7 @@ void HashMapTest::testInsert()
 		assert (it != hm.end());
 		assert (it->first == i);
 		assert (it->second == i*2);
+		assert (hm.count(i) == 1);
 		assert (hm.size() == i + 1);
 	}