In view of the contradictory results of earlier reports regarding bone mass in patients with non-insulin-dependent diabetes, we measured bone mass using dual X-ray absorptiometry and ultrasound measurements of the right calcaneus in 36 type 2 diabetic subjects, i.e. 21 men and 15 postmenopausal women aged 40-65 years, and compared their bone mass to a sex- and age-matched control group. We also measured several metabolic parameters in the diabetic population and studied the relationship between these metabolic parameters and the bone parameters using correlation analysis. We found a tendency to higher bone mass in the diabetic subjects compared to the normal controls. In the Type 2 diabetic postmenopausal women, fat mass and lean body mass correlated positively with total body bone mineral density (BMD) (r = 0.53 and 0.68), and with total body bone mineral content (BMC) (r = 0.58 and 0.77). Insulin sensitivity (GDR/I) correlated negatively with total body BMC and BMD (r = -0.68 and -0.61). Serum insulin correlated positively with the same bone parameters. When controlling for fat mass or lean body mass using a multiple regression analysis, the correlation between insulin sensitivity and BMD became non-significant. This suggests that body mass is a more important determinant of BMD than hyperinsulinaemia or insulin resistance in diabetic women. Among the diabetic men there was a significant positive correlation between lean body mass and BMC (r = 0.66), between serum oestrone and BMD (r = 0.49) and between serum insulin and femoral neck BMD (r = 0.53).(ABSTRACT TRUNCATED AT 250 WORDS)