The effects of type 2 diabetes mellitus (T2DM) on bone volumetric density, bone geometry, and estimates of bone strength are not well established. We used peripheral quantitative computed tomography (pQCT) to compare tibial and radial bone volumetric density (vBMD, mg/cm(3)), total (ToA, mm(2)) and cortical (CoA, mm(2)) bone area and estimates of bone compressive and bending strength in a subset (n = 1171) of men (> or =65 years of age) who participated in the multisite Osteoporotic Fractures in Men (MrOS) study. Analysis of covariance-adjusted bone data for clinic site, age, and limb length (model 1) and further adjusted for body weight (model 2) were used to compare data between participants with (n = 190) and without (n = 981) T2DM. At both the distal tibia and radius, patients with T2DM had greater bone vBMD (+2% to +4%, model 1, p < .05) and a smaller bone area (ToA -1% to -4%, model 2, p < .05). The higher vBMD compensated for lower bone area, resulting in no differences in estimated compressive bone strength at the distal trabecular bone regions. At the mostly cortical bone midshaft sites of the radius and tibia, men with T2DM had lower ToA (-1% to -3%, p < .05), resulting in lower bone bending strength at both sites after adjusting for body weight (-2% to -5%, p < .05) despite the lack of difference in cortical vBMD at these sites. These data demonstrate that older men with T2DM have bone strength that is low relative to body weight at the cortical-rich midshaft of the radius despite no difference in cortical vBMD.