Two patients with ankylosing spondylitis had acute iridocyclitis that recurred with remarkable frequency. Both patients were treated with a combination of hydroxychloroquine sulphate and non-steroid anti-inflammatory drugs (ketoprofen and sodium diclofenac in the first patient; ketoprofen in the second). The uninterrupted treatment lasted 13 months in the first case and 10 in the second. In neither patients did any further attacks of iridocyclitis occur during the above-mentioned treatment.