Diabetes mellitus is an important and increasing cause of morbidity and mortality in sub-Saharan Africa. Accurate epidemiological studies are often logistically and financially difficult, but processes of rural-urban migration and epidemiological transition are certainly increasing the prevalence of type 2 diabetes. Type 1 disease is relatively rare, although this may be related to high mortality. This diabetic subgroup appears to present at a later age (by about a decade) than in Western countries. Variant forms of diabetes are also described in the continent; notably 'atypical, ketosis-prone' diabetes, and malnutrition-related diabetes mellitus. These types sometimes make the distinction between type 1 and type 2 diabetes difficult. Interestingly, this is also a current experience in the developed world. As more detailed and reliable complication studies emerge, it is increasingly apparent that African diabetes is associated with a high complication burden, which is both difficult to treat and prevent. More optimistically, a number of intervention studies and twinning projects are showing real benefits in varying locations. Future improvements depend on practical and sustainable support, coupled with local acceptance of diabetes as a major threat to the future health and quality of life of sub-Saharan Africans.