We have compared the sensitivity of the polymerase chain reaction (PCR) as a diagnostic tool against conventional microscopical diagnostic techniques in patients with cutaneous leishmaniasis from the Sudan. Twenty-eight patients were diagnosed according to clinical criteria followed by microscopical examination of histological sections and slit or impression smears. The PCR had a sensitivity of 86% when used alone, and 93% when combined with Southern blotting. In contrast, microscopy of histological sections had a sensitivity of 76% and slit and impression smears of only 55% and 48%, respectively. The PCR should be considered as a valuable and sensitive diagnostic tool in the diagnosis of cutaneous leishmaniasis; it has the added advantage of identification of the species of Leishmania causing the lesion.