Abstract: The ability of soil yeasts, (Candida tropicalis, Geotrichum candidum, G. capitatum, Rhodotorula minuta and R. rubra) to produce extra cellular protease in vitro was investigated. It appeared that the soil yeasts were proteolytic, with the exception of the yeast C. tropicalis. Production of extra cellular protease led to a marked reduction in pH of the medium. G. capitatum followed by G. candidum were excellent proteolytic producers, and they were the most active yeast in this process, both R. minuta and R. rubra were average producers. C. tropicalis failed to produce protease enzyme with exception of trace amount towards the end of incubation temperature 30°C. The optimum incubation temperature for maximum proteolytic activity was 30 °C. The maximal proteolytic activity was attained in culture medium supplemented with maltose as a sole carbon source. Also peptone was found to be the most suitable nitrogen source for protease production by soil yeasts selected.