Bone loss during immobilisation is well documented. Currently, the only means of studying this in human beings is bed rest, which is resource intensive and inconvenient for the subjects. Unilateral lower limb suspension (ULLS) has been suggested as an alternative, but has not previously been demonstrated to cause bone loss. The main aim of our study was to test the hypothesis that ULLS would cause bone loss determined by peripheral quantitative computed tomography (pQCT). We investigated eight young healthy volunteers (19.1±0.7 years, BMI 22.4±2.6 kg/m^2), who underwent ULLS for 24 days; their right foot was suspended with a strap attached to the shoulder so the knee angle was 10 degrees. They wore a left shoe with a 7.5 cm sole to allow clearance of the right foot and used bilateral crutches to perambulate. Bone scans were obtained by pQCT from the distal epiphyses and from the diaphyses of the tibia in each leg twice before suspension, at 7, 14 and 21 days of the ULLS, and at days 4, 9, 35 and 90 of recovery. After 21 days of ULLS, bone mineral content of the peripheral portion of the epiphysis of the suspended tibia was reduced by 0.89±0.48% (from 280.9±34.5 mg/mm to 278.4±34.2 mg/mm, p < 0.001). No changes were observed in its central portion or in the unsuspended tibia. In the peripheral epiphyseal portion, significant bone loss (by 0.32±0.54%, p=0.045) occurred as early as the seventh day of ULLS.