An unusual case of meconium peritonitis is reported. A neonate presented with a huge multiseptate effusion in the peritoneal cavity in relation with a small bowel perforation. No calcification was visible. Such a presentation cannot be included in one of the classical types of meconium peritonitis. It could be due to a bowel perforation occurring immediately before birth and could therefore be related to a mixed fibroadhesive and generalized form.