Sir, Ankylosing spondylitis (AS) is a chronic inflammatory condition that causes chronic back pain and spinal fusion, often resulting in severe disability and increased morbidity. Whilst non‐steroidal anti‐inflammatory drugs (NSAIDs) are the mainstay of treatment, they only offer symptomatic aid and there is a pressing need for drugs that affect the disease process itself. Of potential disease modifying drugs, sulphasalazine [1] has shown some short‐term benefit in alleviating symptoms of spinal pain and morning stiffness, but this appears to be transient at best. Methotrexate, used extensively in rheumatoid arthritis [2], has also shown some promise in the treatment of AS. In an open study [3], improvement in C‐reactive protein (CRP) and erythrocyte sedimentation rate (ESR) and reduction of symptoms of pain were demonstrated in patients with AS taking methotrexate; however this study only involved 11 patients and, whilst intriguing, was too small to draw valid conclusions. We therefore set out to design a randomized, double‐blind, placebo‐controlled observer study to determine the potential role of methotrexate in controlling disease activity for patients with AS using the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) [4], and to assess any improvement in metrology using the Bath Ankylosing Spondylitis Metrology Index (BASMI) [5].