Message Passing Interface (MPI) is an important standard that allows message-passing applications to run on many heterogeneous message-passing distributed systems without any change. There are a tremendous number of MPI implementations that are, however, mainly dedicated for traditional distributed systems. Most of these implementations consume a significant amount of resources. In addition to the high resource consumption, the existing MPI implementations are not trivially applicable (if at all) to run on embedded systems. After presenting the motivations for designing and implementing a new MPI implementation for heterogeneous embedded systems, this paper presents an innovative technology for achieving MPI implementation, called Lightweight MPI (LMPI), for embedded systems. Then, it presents a prototype implementation of LMPI. Lastly, this paper presents performance analysis by comparing the resource consumption of MPICH and LMPI implementations on a cluster of workstations.