The focus of this prospective, observational study was to determine the effect of sport-specific training and calcium intake on bone mineral density (BMD) in female master cyclists, runners and non-athletes. Thirty women (12 cyclists, 9 runners, 9 controls), mean age of 49.6 +/- 7.9 years, were assessed at baseline and 18 months for calcium intake (4-day records), current exercise activity (recall questionnaire), and BMD of the lumbar spine and hip (DXA). A three (cyclists, runners, controls) by two (0 and 18 months) repeated measures ANOVA demonstrated a significant interaction effect of sport and time at the femoral neck (p <.04). Tukey post hoc analysis indicated that the BMD of the femur was maintained in cyclists and runners but declined in controls (p <.05). A significant time effect was noted in BMD at the lumbar spine (p <. 001) and the trochanter (p <.003). BMD of the lumbar spine was maintained in runners but declined in cyclists (p <.007) and in controls (p <.03), while trochanteric BMD declined in all groups (p <.01). No significant interaction effect of sport and dietary calcium intake was noted for BMD at any site.