Sulphasalazine has been shown to have an effect in patients with spondyloarthropathies, but the clinical indication for its use is controversial and its long term effect has not yet been evaluated. Treatment with sulphasalazine was analysed retrospectively in a group of 372 patients with a wide range of spondyloarthropathies to determine subsets of patients showing differential effects of the drug. One hundred and one patients received sulphasalazine at a mean daily dose of 2 g (ankylosing spondylitis, 54 patients; psoriatic arthritis, 21 patients; reactive arthritis, four patients; arthritis related to inflammatory bowel disease, six patients; undifferentiated spondyloarthropathy, 16 patients). A comparison between treated and untreated patients suggests that only patients with active and severe disease were treated whatever the precise diagnosis or the amount of axial disease in the spondyloarthropathy. After six months of treatment improvement was noted in 59 patients unrelated to their subgroup or amount of axial disease. After a mean follow up of 20 months, 37 patients were still receiving treatment, 33 had discontinued the drug because of inefficacy, 14 because of side effects, six because of remission of the disease, and 11 for other reasons. Comparison between the beginning and end of treatment showed a statistically significant decrease in morning stiffness, erythrocyte sedimentation rate, and daily dose of non-steroidal anti-inflammatory drugs (NSAIDs). It is concluded that: (a) a low percentage of patients with spondyloarthropathy have active disease requiring treatment with sulphasalazine despite the use of NSAIDs (27% in this study); (b) in this subgroup of patients sulphasalazine seems to be of clinically relevant benefit in 59%; and (c) this benefit does not seem to be correlated with either the precise diagnosis of spondyloarthropathy or the amount of axial disease.