During 1996 and 1997, a steam and water separator used in the nuclear power industry was tested with hydrocarbon fluids to evaluate its potential for use in the hydrocarbon production industry. Prior to testing with hydrocarbon fluids, a nondimensional parameter was developed from a simple model of the second-stage centrifugal separator to correlate existing liquid separation efficiency data for this separator using steam and water. This paper outlines the development of the nondimensional correlating parameter and presents comparisons of liquid separation efficiency with steam and water and hydrocarbon fluids using this parameter.