Vertebral fractures are considered the most common fractures in osteoporosis. Nevertheless, little is known about the epidemiology of these fractures, especially in men. Therefore, the incidence of vertebral fractures was studied in 3469 men and women from the Rotterdam Study. Spinal radiographs were obtained at baseline and again after a mean follow-up of 6.3 years. The follow-up radiographs were scored for vertebral fractures using the McCloskey-Kanis assessment method. Whenever a vertebral fracture was detected, the radiograph was compared with the baseline radiograph. If this fracture was not already present at baseline, it was considered an incident fracture. The incidence increased strongly with age, ranging from 7.8/1,000 person years (PY) at ages 55-65 years to 19.6/1,000 PY at ages over 75 years for women, and 5.2-9.3/1,000 PY for men, respectively. Analyses repeated in strata of presence or absence of prevalent vertebral fractures showed that both in men and in women, the increase in incidence with age was almost exclusively observed in subjects with one or more prevalent fractures present at baseline. For both genders, the incidence of vertebral fractures doubled per SD decrease in lumbar spine or femoral neck bone mineral density (BMD). This study shows that overall, the incidence of vertebral fractures is higher in women-than in men. In both genders, the incidence increases with age. Furthermore, the presence of a prevalent vertebral fracture and a low BMD are strong independent predictors of incident vertebral fractures in men and women.