A case–control study was conducted between 1985 and 1987 in the Gezira‐Managil area of central Sudan to assess the major predictors of haematemesis. Eighty‐four patients who had suffered at least one attack of oesophageal bleeding and had schistosomal periportal fibrosis demonstrated by ultrasonography were compared with 173 subjects without bleeding but with ultrasonographic evidence of periportal fibrosis. A splenic longitudinal dimension of more than 11 cm, periportal fibrosis worse than grade I and varices more than grade I were independently associated with a significant risk of variceal bleeding. Age, sex, presence of a palpable liver and portal vein diameter were not associated with a significant risk of bleeding after adjustment for potential confounding variables. Factors identified in this study could be helpful in the prophylactic management of patients with complicated schistosomiasis. Copyright © 1994 British Journal of Surgery Society Ltd.