In this study, the action of low-intensity pulsed ultrasound for 20 min/day, during twenty days, was analyzed in an attempt to revert bone loss in the proximal femur of osteopenic rats. Although the quantitative results of bone mineral content (BMC) demonstrated no significant difference among the groups ( P > 0.05), the histologic investigations have shown the occurrence of recent bone formation not observed in the nontreated group. Moreover, the treated femur presented less microarchitectural deterioration than the nontreated group. These results suggest that the low-intensity ultrasound can interfere in a positive way on osteoporosis.281114118