An irreducible atlanto-axial rotatory dislocation(so-called fixation) is an extremely rare deformity. Its stricking features are the delay in diagnosis and the persistent clinical and roentgenographic deformities. The diagnosis is suggested by the plain roentgenograms and is confirmed by operation. A 9 year-old boy having the atlanto-axial rotatory fixation was examined at Pohang St. Mary's Hospital in July 1985 and was treated with skull traction followed by Gallie fusion. He was followed up over a year, and had satisfactory result at last follow-up.