The main aim in this study was to determine the incidence of radiographically demonstrable calcification of the vas deferens (CVD) in adult diabetics. The second purpose was to relate the CVD to the severity and duration of the diabetes and to associated vascular calcification. Of 100 male diabetics, 11 had CVD. There was no true correlation between the incidence or duration or severity of diabetes and the associated vascular calcification. CVD is not specific for diabetes but is highly suggestive, certainly more so than is vascular calcification. From the material surveyed in this study it appears that most CVD is related to degeneration in the parietal structure rather than to infection in the lumen of the vas. About 70% of men with CVD can be expected to have diabetes.