The presence of lipase in 56 extremely halophilic bacteria was studied by using a plate method with Tweens 20, 40, and 80 as substrates for the enzyme. Thirty-five strains were positive and 21 were negative. Halobacterium salinarium did not hydrolyze any of the Tweens tested. H. cutirubrum hydrolyzed Tween 20 and 40. Micrococcus morrhuae hydrolyzed all Tweens tested. The application of lipase in halobacteria as a taxonomical character was emphasized, and its role in the spoilage of fatty products was considered.