Instability and deformity of the cervical spine caused by rheumatoid arthritis is a well known entity. Operative intervention is indicated for patients with progressive deformity and when pain is resistant to conservative treatment. In a series of 39 patients who underwent posterior occipitocervical fusion with a Y plate, 22 patients were observed clinically and radiographically at average 41.5 months after surgery. In 35 of the 39 patients the main indication for surgery was pain, and in 30 of the 39 patients additional neurologic deficit (radiculopathy or myelopathy) was present. Thirty-one of the 39 patients had atlantoaxial instability. The atlantoaxial instability was associated with cranial migration of the dens in 19 patients. According to the classification of Conaty and Mongan 77.3% patients had satisfactory results and 22.7% had unsatisfactory results. Of the 30 patients with neurologic deficit, nine patients had a significant improvement. No patient had a worse result after surgery. Solid fusion was seen in all 22 patients at followup. Seven patients experienced complications directly related to the surgical procedure. Posterior fixation combined with anterior decompression in the presence of spinal stenosis represents a useful and safe method to treat instability and deformity caused by rheumatoid arthritis. Early surgical procedures may reduce the complication rate.