The radiographs of 28 patients with bladder exstrophy and five with cloacal exstrophy were reviewed at an average age of 8 years 3 months to assess congenital vertebral malformations. Fourteen malformations in 11 patients were noted, including abnormal lumbosacral segmentation in five, congenital scoliosis and kyphosis in four, partial sacral agenesis in three, and interpedicular lumbar widenings in two. These findings are explained by an abnormal embryologic development of the spine and cloaca between 4 and 6 weeks of intrauterine life. We recommend entire spinal radiographs in these patients.