A case is presented in which extension of meconium peritonitis through muscular defects in the diaphragm lead to intrathoracic calcifications diagnosed sonographically at 23 weeks of gestation. There were three diaphragmatic defects, two small ones corresponded to foramina of Morgagni and one large posterior defect that did not correspond to the foramen of Bochdelak. There were three additional muscular defects: one in the rectus abdominus and two, bilaterally, in the loins. Despite long-standing fetal ascites and fresh intraperitoneal meconium at laparotomy, postoperative progress was uneventful. The baby did not have other dysmorphic features except for a single palmar crease, the chromosomes were normal, and the baby did not have cystic fibrosis. Follow-up examination at 10 months showed a thriving infant with mild hypotonia and developmental delay, but no respiratory or gastrointestinal problems.