In this paper, Dick Ashford, Philippe Desjeux and Peter deRaadt attempt to estimate the total number of people at risk of acquiring disease caused by infection with Leishmania spp. In many areas a very small risk is distributed among large numbers of people so, although the number of people at risk may be large, the number of infections may be very small. An estimate of the global annual incidence of new cases has also been made. This refers to reported clinical disease and probably grossly underestimates the number of infections. The methods by which the estimates have been made are specified so that they, as well as the estimates themselves, may be criticized and modified with some degree of objectivity.