Sixty consecutive patients with capsulitis of the shoulder (including those with shoulder-hand syndrome) seen in our clinic since 1971 underwent an oral glucose tolerance test (5 with previously recognized diabetes were excluded from this test). Capsulitis was primary in 35, secondary to other factors in 25 subjects. Females (34) out-numbered males (26). Their ages ranged from 40 to 72 years (mean age: 54 years). Sixty control subjects matched for age and sex with the 60 "capsulitis" patients underwent the same OGTT (except one with previously recognized diabetes). We have found diabetes in 17 out of 60 patients with capsulitis according to Hayner's criteria (12 according to Jackson's criteria) versus 7 (2 according to Jackson's criteria) in the 60 control subjects. The difference is statistically significant by both methods, with a p value of less than 0.02).