Roentgenograms of 28 patients with Down's syndrome were reviewed with emphasis on all previously reported abnormalities and any possible additional ones. Most of the abnormalities occurred with the same frequency as previously reported, but some less frequently reported findings were also seen. One abnormal vertebral measurement found in this series may be an additional stigma of Down's syndrome. All of the 27 cases studied cytogenetically had chromosomal abnormalities consistent with this disease. This study emphasizes the need for roentgenologic norms for the Japanese, and the desirability of combining chromosome studies with roentgenological abnormalities and clinical observations in diagnosing Down's syndrome. 19 references, 2 figures, 5 tables.