Lumbar spine, total body, and regional bone mineral densities (BMDs) were measured in eumenorrheic and amenorrheic runners and triathletes by using dual-energy X-ray absorptiometry (Lunar DPX). Values were also compared with age- and weight-matched reference data from the Lunar British database. The amenorrheic group had significantly lower lumbar spine (P = 0.003), arm (P = 0.018), trunk (P = 0.014), and total spine (P < 0.0001) BMDs compared with the eumenorrheic group and significantly lower lumbar (P = 0.002) and total spine (P < 0.001) values compared with the reference controls. Leg (P = 0.009) and arm (P < 0.001) densities were significantly higher than controls. All regions, apart from the lumbar spine, were significantly higher in the eumenorrheic group compared with the reference group. There were no within-group differences for the runners and triathletes. Compared with the eumenorrheic athletes, the amenorrheic women had significantly later age of menarche (P = 0.0032). The type of physical activity undertaken by these athletes can compensate for the loss of menses at the majority of skeletal sites with the exception of the spine.