- Open MPI (a project combining technologies and resources from several other projects (FT-MPI, LA-MPI, LAM/MPI, and PACX-MPI))
- MPICH (Argonne National Laboratory).
- UNIFY (Mississippi State University).
- CHIMP (Edinburgh Parallel Computing Centre).
- LAM (Ohio Supercomputer Center).
- MPI for the Fujitsu AP1000 (Australian National University).
- Cray MPI Product for the T3D (Cray Research and the Edinburgh Parallel Computing Center).
- IBM's MPI for the SP.
- SGI's MPI for 64-bit mips3 and mips4.
- PowerMPI for Parsytec Systems.
- HP's MPI implementation.
