diff --git a/Foundation/include/Poco/InflatingStream.h b/Foundation/include/Poco/InflatingStream.h
index 960ccf3fe..ca20cb07e 100644
--- a/Foundation/include/Poco/InflatingStream.h
+++ b/Foundation/include/Poco/InflatingStream.h
@@ -85,6 +85,7 @@ public:
 protected:
 	int readFromDevice(char* buffer, std::streamsize length);
 	int writeToDevice(const char* buffer, std::streamsize length);
+	int sync();
 
 private:
 	enum 
diff --git a/Foundation/src/DeflatingStream.cpp b/Foundation/src/DeflatingStream.cpp
index 28c9dbb4a..c0c722f4e 100644
--- a/Foundation/src/DeflatingStream.cpp
+++ b/Foundation/src/DeflatingStream.cpp
@@ -159,6 +159,7 @@ int DeflatingStreamBuf::close()
 				_zstr.avail_out = DEFLATE_BUFFER_SIZE;
 			}
 		}
+		_pOstr->flush();
 		_pOstr = 0;
 	}
 	return 0;
@@ -188,6 +189,7 @@ int DeflatingStreamBuf::sync()
 		_zstr.next_out  = (unsigned char*) _buffer;
 		_zstr.avail_out = DEFLATE_BUFFER_SIZE;
 	}
+	_pOstr->flush();
 
 	return 0;
 }
diff --git a/Foundation/src/InflatingStream.cpp b/Foundation/src/InflatingStream.cpp
index 6a55f8bc1..77ecb500b 100644
--- a/Foundation/src/InflatingStream.cpp
+++ b/Foundation/src/InflatingStream.cpp
@@ -253,6 +253,14 @@ int InflatingStreamBuf::writeToDevice(const char* buffer, std::streamsize length
 }
 
 
+int InflatingStreamBuf::sync()
+{
+	int n = BufferedStreamBuf::sync();
+	if (!n && _pOstr) _pOstr->flush();
+	return n;
+}
+
+
 InflatingIOS::InflatingIOS(std::ostream& ostr, InflatingStreamBuf::StreamType type):
 	_buf(ostr, type)
 {