Visceral leishmaniasis was detected incidentally in a patient with acute lymphoblastic leukaemia in remission, during maintenance therapy. Absence of fever, a normal haemogram, normal serum globulins, a negative serology and testicular involvement were the hallmarks of the case. Treatment with sodium stibogluconate (20 mg/kg for 55 days) failed. Subsequent therapy with pentamidine resulted in complete parasite clearance. Prolonged therapy with pentavalent antimony compounds or a higher dose of second line drugs such as pentamidine are recommended for complete clearance.