The presence of an enlarged transverse process on one or both sides of the last lumbar vertebra is a common congenital anomaly of the lumbar vertebra. It is thought to be a genetic or developmental anatomical variant. The first reported assimilation of the fifth lumbar vertebra into the sacrum associated with low back pain was in 1917 by Bertolotti. However, clinical significance of lumbosacral transitional vertebra has not been fully considered due to lack of scientific investigations dealing with it. We experienced a case of symptomatic lumbosacral transitional vertebra during management of low back pain. Low back pain was relieved after infiltration of local anesthetics and steroid into the false joint of lumbosacral transitional vertebra. This result may possibly indicate a significant correlation between low back pain and lumbosacral transitional vertebra.