Candida arthritis is a rare event which is a result of direct intraarticular inoculation, or--in compromised host--of hematogenous spread. We report on the case of an 18-month-old boy who experienced such an infection during induction treatment for acute lymphoblastic leukemia with aplastic onset. He was healed by daily systemic amphotericin B administered over a period of 3 wks associated with intravenous flucytosine during the first 2 wks; the treatment was continued with oral administration of ketoconazole for 5 wks. Treatment control was performed by drug monitoring in plasma and synovial fluid, as well as by determination of Candida antigenemia and antibody levels. We consider that the required doses of amphotericin B should be based upon plasma concentrations greater than 0.5 or 1 mg/l to be maintained during 2-3 wks. Providing that there is no resistance, the association with flucytosine may be useful.