A U.S.-U.S.S.R. workshop in the field of multiphase flow systems will be held in Chicago, Illinois in May 1991, organized by Drs. James Hartnett (University of Illinois, Chicago) and Raymond Viskanta (Purdue University) on behalf of the Midwest Universities Energy Consortium, and Dr. Oleg Martynenko of the Luikov Institute of Heat and Mass Transfer, Minsk. The primary objective of the workshop is to identify opportunities for scientifically promising collaborative research partnerships of mutual benefit involving U.S. and Soviet investigators and to prepare proposals for long-term cooperative research projects for submission and competitive review. Multiphase flow problems are of vital concern to a broad range of industries, including petroleum and gas production, power generation, chemicals, and others. However, our understanding of the basic principles and behavior of these systems is quite limited, potentially leading to failures of process design, safety hazards, and limited economic benefit. The complementary expertise and capabilities of the U.S. and Soviet research efforts in this field are expected to contribute toward improved understanding of these processes. This project fulfills the program objective of advancing scientific knowledge by enabling leading researchers in the United States and the U.S.S.R. to combine comple- mentary efforts and capabilities in areas of strong mutual interest and competence in the field of basic scientific research on the basis of equality, reciprocity, and mutuality of benefit.