The working ability of 76 patients with ankylosing spondylitis (AS) diagnosed between 1952 and 1959 was investigated. After 25 years of AS, 48% of the patients were still able to work at their original occupation and only 30% were unable to work at all. 17% of the patients had had to change their occupation and 5% had retired because of age. This finding does not differ from those reported in earlier studies.