The purpose of this study was to compare the insulin-like growth factor-1 (IGF-1) levels and the growth hormone (GH) levels in osteoporotic and nonosteoporotic postmenopausal women. Eleven non-osteoporotic postmenopausal women and 9 women with untreated postmenopausal osteoporosis were included in the study. Bone mineral density (BMD) was assessed by dual energy X-ray absorbtiometry. Serum was assayed for calcium, phosphorus, alkaline phosphatase, bone-specific alkaline phosphatase, parathyroid hormone, IGF-1 and GH levels. IGF-1 levels were 98.8 +/- 43.5 ng/ml for osteoporotic women and 169.8 +/- 50.3 ng/ml for the women with normal BMD (p < 0.05). GH levels were 1.3 +/- 1.1 ng/ml and 1.3 +/- 1.0 ng/ml, respectively. When compared with normal postmenopausal women, IGF-1 levels were found to be lower in women with osteoporosis. IGF-1 seems to play an important role in the development of low bone mass and the present results suggest that IGF-1 is a useful predictor of the presence of osteoporosis.