The Cellognost indirect haemagglutination (IHA) test was compared with conventional techniques, namely, wet blood film examination, stained thin and thick films, animal inoculation and the microhaematocrit centrifugation, for detecting sleeping sickness cases. Sixty-four out of 245 serum samples collected from suspected and some diagnosed cases of the disease were positive by the Cellognost screening test, while only three cases were detected by stained thin film or microhaematocrit centrifugation. Of the 64 cases 45 strongly positive samples were subjected to quantitative assay. Twenty-five of these had anti-Trypanosoma gambiense antibody titres above 1:20 representing active infection in the population. This represented 10.2% of the total sample, and strongly suggested the persistence of the disease in the population.