The 4p- syndrome results from a structural deficiency in chromosome 4. The clinical and radiologic findings in three patients with the 4p- syndrome are presented. Clinical, genetic, and radiologic findings in other reported cases are summarized. A widened interpubic distance with underdevelopment of the bony pelvis and deficiencies in ossification of the cervical spine are prominent radiologic features in our cases. Taken separately, these findings have limited differential diagnostic possibilities which are briefly discussed. The combination of these findings with characteristic clinical abnormalities is very suggestive of the 4p- syndrome and should prompt karyotyping for confirmation.