Human T-cell leukaemia virus 1 (HTLV-1) is a retrovirus aetiologically associated with adult T-cell leukaemia (ATL), tropical spastic paraparesis (TSP) and possibly multiple sclerosis (MS) in humans. Three founder lines of transgenic mice containing the HTLV-1 tax gene under the control of the viral long terminal repeat (LTR) have previously been shown to develop neurofibromas. Further analysis of these animals has now revealed that they also develop an exocrinopathy involving the salivary and lachrymal glands. This pathology resembles Sjögren's syndrome, a disease of presumed autoimmune aetiology, features of which are sometimes reported in HTLV-1 associated conditions. Mice with an HTLV-1 tax transgene might be a useful model for studying the development of Sjögren-syndrome-like pathology.