BACKGROUND This study examined the effects of 4 months of resistive training in postmenopausal women on glucose metabolism and peripheral tissue sensitivity to endogenously released insulin. METHODS Thirteen moderately obese (30-49% body fat) postmenopausal women (50-65 years) participated in the study. The six more obese women were enrolled in the resistive training with weight loss (RT & WL) program, while the remainder participated in resistive training alone (RT). beta-cell sensitivity to glucose and peripheral tissue sensitivity to endogenously released insulin were examined during hyperglycemic clamps (7.9 mmol/L above basal) before and after the intervention(s). RESULTS The RT program resulted in a significant improvement in upper and lower body strength (p < .01) in all subjects. Body weight, fat mass, and percent body fat decreased with RT & WL (p < .001), but did not change with RT alone. There was no change in fat-free mass or maximal oxygen consumption after the intervention(s). Insulin response during the last 20 min of the 2 hr hyperglycemic clamps (7.9 mmol/L above basal plasma glucose levels) decreased after the intervention(s) in the entire group by 29% (p < .01), but decreased more in the group that lost weight (43%, p < .05) than in women who remained weight stable (16%, p = .05). Glucose utilization did not change. CONCLUSIONS RT alone, or in combination with WL, increases insulin action and reduces hyperinsulinemia in postmenopausal women. This suggests that RT has the potential to ameliorate and perhaps prevent the development of insulin resistance and may reduce the risk for glucose intolerance and non-insulin-dependent diabetes mellitus (NIDDM) in postmenopausal women.