Treatment outcome was determined among a cohort of travellers who returned to the UK between February 2000 and February 2001 with New World cutaneous leishmaniasis caused by species of the Leishmania (Viannia) subgenus. Among 18 patients who completed treatment with 20 mg/kg/d of i.v. sodium stibogluconate (NaSb) for 20 d, early relapse of disease occurred in 2 patients with regional dissemination in 1 and mucocutaneous involvement in the other. Drug susceptibility testing in vitro of the clinical isolate from 1 of these patients confirmed tolerance to high concentrations of NaSb.