In object-oriented development of distributed computing system software, one of the important tasks is t o cluster objects into modules f o r achieving high performance, which is heavily affected by intermodule communication and the degree of parallel execution of modules. In this paper, a clustering algorithm is presen,ted based on reducing intermodule communication and increasing concurrency for module execution as well us satisfying user's specifications on clustering of objects. A n example is given to illustrate the clustering algorithm.