diff --git a/JSON/include/Poco/JSON/Array.h b/JSON/include/Poco/JSON/Array.h
index d1836c52d..fb833b30f 100644
--- a/JSON/include/Poco/JSON/Array.h
+++ b/JSON/include/Poco/JSON/Array.h
@@ -57,7 +57,7 @@ class Object;
 class JSON_API Array
 {
 public:
-	typedef std::vector<Dynamic::Var> ValueVector;
+	typedef std::vector<Dynamic::Var> ValueVec;
 	typedef SharedPtr<Array> Ptr;
 
 	Array();
@@ -69,10 +69,10 @@ public:
 	virtual ~Array();
 		/// Destructor
 
-	ValueVector::const_iterator begin() const;
+	ValueVec::const_iterator begin() const;
 		/// Returns iterator
 
-	ValueVector::const_iterator end() const;
+	ValueVec::const_iterator end() const;
 		/// Returns iterator
 
 	Dynamic::Var get(unsigned int index) const;
@@ -148,26 +148,26 @@ public:
 		/// Removes the element on the given index.
 
 private:
-	ValueVector _values;
+	ValueVec _values;
 };
 
 
-inline Array::ValueVector::const_iterator Array::begin() const
+inline Array::ValueVec::const_iterator Array::begin() const
 {
 	return _values.begin();
 }
 
 
-inline Array::ValueVector::const_iterator Array::end() const
+inline Array::ValueVec::const_iterator Array::end() const
 
 {
 	return _values.end();
 }
 
 
-inline unsigned int Array::size() const
+inline std::size_t Array::size() const
 {
-	return _values.size();
+	return static_cast<std::size_t>(_values.size());
 }
 
 
diff --git a/JSON/include/Poco/JSON/Object.h b/JSON/include/Poco/JSON/Object.h
index 37288e1cf..2de10f0c3 100644
--- a/JSON/include/Poco/JSON/Object.h
+++ b/JSON/include/Poco/JSON/Object.h
@@ -186,9 +186,9 @@ inline void Object::set(const std::string& key, const Dynamic::Var& value)
 }
 
 
-inline unsigned int Object::size() const
+inline std::size_t Object::size() const
 {
-	return _values.size();
+	return static_cast<std::size_t>(_values.size());
 }
 
 
diff --git a/JSON/src/Array.cpp b/JSON/src/Array.cpp
index 434ab80e5..b58fbf8d8 100644
--- a/JSON/src/Array.cpp
+++ b/JSON/src/Array.cpp
@@ -115,7 +115,7 @@ void Array::stringify(std::ostream& out, unsigned int indent) const
 	if ( indent > 0 )
 		out << std::endl;
 
-	for(ValueVector::const_iterator it = _values.begin(); it != _values.end();)
+	for(ValueVec::const_iterator it = _values.begin(); it != _values.end();)
 	{
 		for(int i = 0; i < indent; i++)
 		{