Acquired (non-Meckel's) jejunoileal diverticulosis is an uncommon disease, generally characterised by vague and unspecific symptoms. This rare condition is mainly expressed as acute complications: gastrointestinal haemorrhage, mechanic obstruction of the small intestine or perforated diverticulum, requiring urgent surgical intervention. The authors report a case of this unusual clinical occurrence characterized by a picture of abdominal pain due to perforation of jejuneal diverticulum. The final etiological diagnosis was possible only during surgery.