In some ranges of mass ratio and mass-radius exponent, it is shown that there are inconsistencies in Faulkner’s (1971) analytic model of a mass-conservative circular binary system that is evolving via the combined processes of mass exchange through Roche lobe overflow and emission of gravitational waves. These inconsistencies occur because of the use of an assumption that the time derivative of the Roche lobe radius is equal to that of the stellar radius. Consequently, his equations for the rate of mass exchange and orbital period variations are generally invalid. ©1999 American Institute of Physics.