Leishmanial infections include three major clinical syndromes: visceral, cutaneous, and mucosal leishmaniasis. Visceral leishmaniasis, usually due to Leishmania donovani, has received increasing attention in the United States because of the growing number of cases seen in AIDS patients and the occurrence of viscerotropic L. tropica disease among Persian Gulf war participants. Cutaneous leishmaniasis is a relatively benign disease caused by L. Mexicana and L. (Viannia) species in the New World, and L. major, L. tropica, and L. aethiopica in the Old World. Many of these cutaneous lesions are self-healing, and treatment recommendations vary and continue to undergo evolution and study. Mucosal disease, caused by Leishmania (V.) braziliensis, is difficult to diagnose as well as to treat. A practical approach to the clinical presentation, diagnostic measures, and some treatment options of these syndromes is presented in relation to specific case studies.