A national survey was conducted in Mali between 1986 and 1990 to determine the geographical distribution of urinary schistosomiasis in order to define an ecologically based national schistosomiasis control programme. Fifty six thousand two hundreds and sixty five individuals randomly selected from 323 villages in the nine ecologically defined areas of the whole country were submitted to urine examination using Filtration Technique. In villages along the Niger and Senegal rivers, in the Dogon Plateau and Office du Niger areas, the prevalence of Schistosoma haematobium infection was the highest, respectively 41.8%, 53.1%, 59.4% et 62.9%. In these areas, more 70% of children aged 7 to 14 years were infected. In the Soudanian and North-Soudanian areas, the prevalence were below 10% and respectively only 5.3% and 11.5% of children aged 7 to 14 years were infected. It is concluded that Schistosoma haematobium infection is of public health importance in dam and irrigation areas and in areas along the Niger and Senegal rivers namely in Kayes, Koulikoro, Segou, Mopti regions and in Bamako district. These areas should be considered as priority areas for active control interventions. The interventions should include community-based mass chemotherapy with praziquantel after community diagnostic using urine examination in school aged children and a good monitoring system.