The kinetic behaviour of an industrially important thermostable extracellular proteolytic enzyme produced by a locally isolated species, Rhizopus oryzae (RO) in shake flask culture, has been studied. Michaelis constant (K-m) and maximum reaction velocity (V-max) for this enzyme nave been evaluated at different temperatures and substrate conditions. The inhibition coefficient (K-i) in presence of metal ions have also been estimated. An empirical correlation for the reaction velocity (V) has been developed as a function of temperature, pH substrate and enzyme concentrations.