In order better to define the prevalence and characteristics of idiopathic vertebral sclerosis, we evaluated the roentgenograms of 1,391 individuals > 35 years of age) for the presence or absence of idiopathic vertebral sclerosis. One hundred two radiographs showed evidence of idiopathic vertebral sclerosis, a prevalence rate of 5% in this population. For the first time, a roentgenographic classification is offered. These “cases” were then classified into Types I-IV, based on the pattern and location of the sclerosis. The radiologic and demographic characteristics of Type I correlate most closely with previous studies that have investigated the association of vertebral sclerosis with chronic back pain. Women predominated in age-specific classifications; the female-to-male ratio in Type I was 4:1, a reproducible finding in previous studies. The large sample available for study supports the conclusion that this is an accurate estimate of the prevalence rate of idiopathic vertebral sclerosis.