INTRODUCTION: As life expectancy in the population rises, osteoporotic fractures are seen most frequently in the proximal femur and the vertebral column. In balloon kyphoplasty and vertebroplasty, we have two minimally invasive treatment procedures available. Although they have both been controversially discussed in studies, they have seldom been directly compared. MATERIALS AND METHODS: Between 2002 and 2004, patients with fresh thoracic or lumbar single-segment vertebral compression fractures not involving neurological deficits were treated by balloon kyphoplasty (n = 30) or vertebroplasty(n = 30) using PMMA cement, and the results of the two interventions were compared in a prospective, nonrandomised cohort study. Surgery was indicated when patients had painful, dislocated fractures of type A1 and type A3 according to Magerl's classification. The outcome of treatment was assessed with special reference to the angle of kyphosis, back pain (VAS), health-related quality of life (SF-36) and complications. RESULTS: At the time of the follow-up examination, significant improvement in the angle of kyphosis was found to have been achieved both by kyphoplasty and by vertebroplasty (P < 0.001 and P = 0.002, respectively). Comparison showed that correction of the angle was significantly (P < 0.001) better in the kyphoplasty group. Both surgical procedures led to significant (P < 0.001) attenuation of the patients' pain; no difference was observed between the groups in the degree of pain relief achieved. There was no demonstrable correlation in either group between the preoperative pain experienced by the patients and the degree of dislocation of their fractures. In both study groups, the quality of life was in keeping with that of a reference group matched for age and sex. Cement leakage was observed in 7% of patients after kyphoplasty and in 33% of patients after vertebroplasty (P = 0.021). Adjacent-level fractures were checked for, but occurred in only one patient in the vertebroplasty group. CONCLUSION: The two surgical procedures were both followed by significant pain relief, and the quality of life was similar regardless of the procedure used. Balloon kyphoplasty led to an ongoing reduction of freshly fractured vertebrae and was followed by a lower rate of cement leakage.