Abstract: The aim of Para++ is to provide a user-level C++ interface to message passing libraries, by encapsulating the notions of processes and inter-processes communications into specific C++ objects and streams. Actually, this abstraction level allows to implement Para++ with any kind of message passing library. Para++'s main idea is to add new C++ io-streams to allows inter-tasks communications. These streams support all generic scalar datatype ({\tt int}, {\tt float}, {\tt double},...), plus some mathematical datatypes ({\tt Vectors}, {\tt Matrix},...) in order to exchange data between co-operating tasks. Para++ has been implemented on top of PVM and MPI.