The unusual association of an omovertebral bone with Sprengel deformity and Klippel-Feil syndrome is a complex bone anomaly of unknown incidence and etiology. However, several cases of this rare disease pattern have been reported in the literature. In this paper, the authors present the case of a 34-year-old woman with a 5-month history of progressive gait ataxia and intermittent urinary incontinence, which was found to be caused by aberrant bone growth into the spinal canal from an omovertebral bone that extended from the left scapula pressing into the C-6 vertebral arch and subsequently causing cervical myelopathy. The patient underwent isolated resection of the omovertebral bone and decompression of the spinal canal, and her functional and neurological outcome was favorable.