Leishmania isolates from patients in the Sudan suffering from either visceral or cutaneous leishmaniasis were characterized using a battery of 12 enzymes. Aspartate aminotransferase separated the L. donovani isolates into 2 distinct zymodemes, but the overall results showed no significant geographical variation among L. donovani isolates. In contrast, the isolates of L. major were polymorphic, exhibiting differences in nucleoside hydrolase, 6-phosphogluconate dehydrogenase, superoxide dismutase, esterase, mannose phosphate isomerase, and aspartate aminotransferase, resulting in the description of 4 new enzymatic variants.