Butterfly vertebra is a rare congenital anomaly associated with syndromes such as Pfeiffer, Jarcho-Levin, Crousen, Alagille. In the literature, only a few cases of butterfly vertebra have been reported as incidental finding. We described a 37-year-old male who had an L3 butterfly vertebra associated with an L4-L5 disc protrusion. Awareness of this anomaly is important for making correct diagnosis. Although this uncommon anomaly is considered to be usually asymptomatic, we suggest that it might increase the incidence of disc herniation, because the condition may alter the spinal biomechanics.