The application of leishmanin and tuberculin skin tests was studied in patients with leishmaniasis in the Sudan. 35 cases of active kala-azar and 3 relapse cases were leishmanin negative. 81% of patients treated for kala-azar showed a positive reaction after 6 months. 17 of 29 patients with post kala-azar dermal leishmaniasis (PKDL) were leishmanin positive. 2 of 16 patients with kala-azar tested with tuberculin were positive; one was diagnosed as tuberculosis. In 7 initially tuberculin negative patients, the tuberculin test became positive after treatment. A new Leishmania major skin test antigen (Pasteur Institute, Iran) was more reactive than other antigens in patients with cutaneous leishmaniasis, mucocutaneous leishmaniasis and PKDL, but not in treated kala-azar cases. In a field study in an area of endemic kala-azar, the new L. major antigen proved more reactive both in individuals previously exposed to L. major (causing cutaneous leishmaniasis) and in those with past exposure to L. donovani. The literature concerning skin testing with leishmanin and tuberculin in kala-azar is reviewed.