PURPOSE: To establish that trachoma is a public health problem in Burundi, and to provide baseline data on the prevalence of active trachoma and unclean faces prior to the commencement of trachoma elimination activities in endemic districts. METHODS: For each of 11 pilot districts, eight collines (hills) (estimated population generally 1000-8000) were selected at random using a population-proportional-to-size technique; from each selected colline, one sous-colline (of which there are generally 3-5 per colline) was selected at random by simple random draw. In each selected sous-colline, all available 1-9-year-old children were examined for clinical signs of trachoma, and for signs of an unclean face (defined as eye discharge, nose discharge and/or presence of one or more flies on the face during the time taken to examine the eyes). RESULTS: A mean of 230 children were examined per sous-colline (range 44-600); in all, 20,659 children were examined in 90 sous-collines of 11 districts. (In one district, 10 rather than eight sous-collines were selected.) In three contiguous districts (Buhiga, Nyabikere and Muyinga) in the country's north-east, the prevalence of the sign "trachomatous inflammation-follicular" (TF) in 1-9-year-olds was >10%. In nine districts, the prevalence of unclean faces was >10%. CONCLUSION: Trachoma is a public health problem in Burundi. Implementation of trachoma control activities is indicated in at least Buhiga, Nyabikere and Muyinga. Further work should be carried out to establish the likely backlog of unoperated trachomatous trichiasis.