To characterize the epidemiology of dysentery (defined as bloody diarrhoea) in Burundi, we reviewed national surveillance data and conducted a household cluster survey including two case-control studies: one at the household, the other at the individual level. We estimated that community incidences for dysentery (per 1000 residents) in Kibuye Sector were 15.3 and 27.3, and that dysentery accounted for 6% and 12% of all deaths, in 1991 and 1992, respectively. Factors associated (P - 0.05) with contracting dysentery were being female, using a cloth rag after defecation, a history of recent weight loss, and not washing hands before preparing food. The attributable risk, at the household level, of not washing hands before preparing food was 30%. Secondary household transmission accounted for at most 1 1 % of dysentery cases. This study suggests that Shigella dysenteriae type 1 may be one of the leading causes of preventable mortality in Burundi and other African countries where effective antimicrobial agents are no longer affordable. Since hands were the most important mode of transmission of S. dysenteriae in this study, communitybased interventions aimed at increasing hand washing with soap and water, particularly after defecation and before food preparation, may be effective for controlling dysentery epidemics caused by S. dysenteriae type 1 in Africa.