Background: Previous studies have found that walking could have positive effects on maintaining Bone Mineral Density (BMD) among postmenopausal women. However the majority of this group tends to be sedentary. Barriers to maintaining regular physical activity among postmenopausal women are found to be the lack of accessibility of physical activity facilities and the convenience and safety of the mode of physical activity. Walking is viewed as an easy, less costly physical activity and could be adopted with limited time and location. Six-month or longer walking interventions, with extra weight bearing, were found to have an effect on maintaining (BMD). It has been less widely investigated whether the same effect can result from a shorter periods of walking intervention and without weight bearing. Objective: Aims to examine the effect of a 12-week walking intervention, without weight bearing, on maintaining BMD among postmenopausal women. Methods: A randomized controlled trail design was used to test the effect of the walking intervention. Participants were recruited from an east township of Taiwan. A total of 57 participants was randomized to either a control (n=28) or intervention group (n=29). Control group participants received a usual care when needed. Participants in intervention group received a 12-week, without-weight-bearing walking intervention. Results: At 12th week follow up, mean change of BMD was similar in two groups (p=.5). Aerobic steps were increased in intervention group. Scores of exercise self-efficacy and exercise outcome expectation were also improved significantly. Conclusions: A 12-week, without-weight-bearing walking intervention may increase postmenopausal women s physical activity, exercise self-efficacy and exercise outcome expectation but the effect on maintaining BMD was not found. Future study testing the effect of longer period, without-weight-bearing walking intervention or vice-versa on maintaining BMD is warranted. Only then maintaining or improving BMD through walking activity among postmenopausal women could be feasible.