We report on two sib fetuses with radiological and morphological findings similar to those of the recently described lethal skeletal dysplasia termed Pacman dysplasia (McKusick, 167220, Am J Med Genet 1993, 45:558-561). The first fetus, a male, was electively terminated after a routine ultrasound study at 20 weeks showed short-limb dwarfism. The second fetus, a female sib, was also electively terminated after similar, abnormal ultrasound findings were noted at 16 weeks of gestation. Similar to Pacman dysplasia, the radiographic appearance was characterized by under-mineralized bone, stippling, rhizomelic and mesomelic shortness, platyspondyly, and a short, broad pelvis. The metaphyses were dense, but the diaphyseal cortices were thin with undermodeled long bones, and there was a deficient trabecular pattern suggesting marrow replacement. Chondro-osseous structure was characterized by deficient trabecular bone formation, a fibrous marrow, and numerous, large, multinucleated osteoclasts lining the endosteal surfaces of the metaphyseal bone. The occurrence of this dysplasia in sibs of differing sex suggests autosomal recessive inheritance.