1. As a defect of suppressor function has been hypothesized in the pathogenesis of coeliac disease, we measured, by monoclonal antibodies, the inducer/suppressor T-cell ratio in adult coeliac disease. 2. No statistical difference was observed between coeliac patients and healthy controls, irrespective of treatment and HLA status. 3. These results do not show an imbalance in the inducer/suppressor T-cell ratio in coeliac disease.