Yersinia enterocolitis with peritonitis and septicaemia developed in a 4-year-old child with thalassemia intermedia and iron overload. It is likely that the illness was exacerbated by continued administration of desferrioxamine, a bacterial siderophore, which facilitated systemic spread of Yersinia. It is recommended that Yersinia enterocolitis be considered in children with iron overload and that desferrioxamine be discontinued and prophylactic antibiotics be administered while Yersinia is sought.