Relapse after chemotherapy using the pentavalent antimonials, sodium stibogluconate and meglumine antimoniate, was assessed in 135 patients diagnosed in the Aba Roba focus of south western Ethiopia during the period 1982-1991. Ten cases relapsed with a mean of 15.6 +/- 16.3 months following treatment. A 15-day course of 10 mg Sbv/kg b.wt. sodium stibogluconate used in 1982/1983 had a better outcome than a 15-day course of 17 mg Sbv/kg b.wt. of meglumine antimoniate used in 1990/1991. The relapse rate among patients treated with sodium stibogluconate 16-20 mg Sbv/kg b.wt. for 20 days in 1985-1990 was comparable to the relapse rate in patients treated with meglumine antimoniate 16-20 mg Sbv/kg b.wt. for 20 days in 1990/1991. Findings are discussed.