Transitional vertebrae (TV) may be one of the risk factors for lumbar disc herniation. It is not clear, however, whether the presence of TV can affect the development of nerve-root symptoms. Our aim was to clarify this relationship. A total of 501 patients with lumbar degenerative disease and nerve-root symptoms was studied in respect of their level and the presence of TV. As a control group, 508 patients without low back pain or nerve-root symptoms were studied to establish the incidence of TV. In patients with disc herniation, the incidence was statistically higher and the mean age lower in patients with TV than in those without. In most patients, the symptomatic disc level was just above the TV. Similarly, in those with stenosis of the spinal canal without spondylolisthesis, the symptomatic disc level was most commonly just above the TV.