Alendronate has been shown to increase bone density among early postmenopausal women. Osteoporosis is common among both Asian and Caucasian women, but most clinical trials have consisted primarily of Caucasian women, and it does not appear that the effectiveness of antiresorptive agents such as alendronate has been compared between the two races. In this study we compared the response of bone density and biochemical markers to alendronate among 136 Asian and 126 Caucasian women who participated in the Early Postmenopausal Interventional Cohort (EPIC) at the Hawaii center. Approximately 40 women of each race were randomly assigned to placebo or to 2.5 mg/day or 5 mg/day alendronate. Bone mineral density (BMD) was measured at the spine, total hip and total body at baseline, 12 months and 24 months; biochemical markers of bone turnover were measured at 6-month intervals. Responses were greater for the 5 mg dose than 2.5 mg, and were similar in the two races. For example, mean (SE) changes in spine BMD at 24 months for Caucasians and Asians, respectively, were –1.9% (0.5%) and –1.9% (0.4%) for the placebo group, 2.0% (0.5%) and 3.4% (0.5%) at 2.5 mg/day and 4.2% (0.5%) for both races at 5 mg/day. Corresponding changes in urinary N-telopeptide collagen crosslinks were –33.6% (5.6%) and –27.8% (5.8%) for placebo, –51.4% (4.0%) and –62.1 (4.3%) at 2.5 mg/day and –70.8% (2.4%) and –73.5% (3.1%) at 5 mg/day. We conclude that (1) the rate of bone loss in untreated Asian and Caucasian postmenopausal women is similar, with the possible exception of the hip; (2) 5 mg alendronate daily provides greater skeletal benefits than 2.5 mg/day in both Asian and Caucasian early postmenopausal women; and (3) the response at 5 mg/day is similar in the two races.