Abstract: Rhizopus sp. a mould of mucor family, excrete lipase when cultured on lipolytic media. The Rhizopus sp. produced a larger clear zone on tributyrin agar medium suggesting its esterase activity. It was further investigated in liquid medium in order to optimize the lipase production conditions under shake culture. Lipase production was found to be maximum with medium containing maltose (1%) and peptone (5%) as carbon and nitrogen sources, respectively with Rhizopus sp. The enzyme production was profoundly influenced by initial pH of the medium and optimum value of this parameter was found to be 6.0. Maximum enzyme production was obtained at 30 °C with a shaking rate of 200 rpm. Ca2+ was found to stimulate lipase production, while it was strongly inhabited by Hg2+. Lipase production was increased about 23.7% under optimized cultivation conditions over olive oil-peptone medium.