To characterise the role of ethnicity in the occurrence of foot ulcer disease in persons with diabetes, we analysed prospectively collected data for persons attending the diabetes clinic at Muhimbili National Hospital (MNH), Dar es Salaam, Tanzania. A case was defined as any adult presenting to MNH with an ulcer at or below the ankle joint during July 1998-June 2005. We documented clinical and epidemiologic characteristics, progress, interventions and outcome. Seven hundred and eight persons met the case definition - 570 (80%) ethnic Africans and 138 (20%) Asian Indians. Ethnic Africans were more likely to present with gangrene (P < 0.01); Indians were more likely to be obese (P < 0.001) or have large vessel disease (P < 0.001). For Africans, intrinsic complications (neuro-ischaemia or macrovascular disease) delayed ulcer healing; for Asian Indians, mode of intervention (e.g. sloughectomy or glycaemic control with insulin or oral agents) determined the same outcome. Indigenous ethnic African and Asian Indian populations with diabetes display contrasting foot ulcer epidemiology. Peripheral vascular disease and gangrene are playing a larger role in ulcer pathogenesis and outcomes for both ethnic groups than was previously thought. Preventive efforts and interventions should be tailored to the two ethnic groups to achieve complete ulcer healing.