Twelve cases of meconium peritonitis were retrospectively reviewed in this study. Five of these patients had cystic fibrosis. Of the patients with cystic fibrosis, intraperitoneal calcifications were present in three (60%) and two (40%) had none. All seven patients (100%) who had meconium peritonitis without cystic fibrosis had abdominal calcifications. These results indicate that the presence of intraperitoneal calcifications does not exclude the diagnosis of cystic fibrosis and that the absence of calcification favors cystic fibrosis. However, a review of the literature indicates the absence of calcification is merely of clue and not definitive as to the etiology of the meconium peritonitis.