Human African trypanosomiasis (HAT) is a vector-borne parasitic disease which has often been considered a rural disease. Population increases in African countries have entailed the spread of urban centres, creating favourable conditions for the appearance of new epidemiological conditions. In Cote d'Ivoire, HAT transmission has been described in the surroundings of towns such as Daloa or Sinfra. In the focus of Bonon, located in central-western Cote d'Ivoire, a medical survey detected 96 patients. The sites visited by the patients every day were geo-referenced and the routes between them recorded. In parallel, an entomological survey of the patients' daily locations enabled the collection of data on the vector. In Bonon, we observed urban cases and tsetse (Glossina palpalis) feeding on men. Trypanosoma brucei gambiense was identified in both man and vector; thus all conditions for possible intra-urban trypanosomosis transmission were met. The consequences of this are discussed regarding the problem of diffusion of the disease.