Rheumatic disease has long been thought to represent an interaction between environmental agents on a background of genetic susceptibility. In this review herpesviruses and retroviruses are considered as possible aetiological agents in autoimmune disease with a particular emphasis on Sjogren\'s syndrome. A possible role for cytomegalovirus, Epstein-Barr virus (EBV), human herpesvirus-6 (HHV-6) and human herpesvirus-8 (HHV-8) is reviewed. We conclude that there is no compelling evidence for the involvement of any of these herpesviruses. Retroviruses, however, are attracting increasing interest. In Man, both Human immunodeficiency virus (HIV) and human T lymphotropic virus type I (HTLV-I) infections cause autoimmune phenomena, including Sjogren\'s syndrome and arthritis in a minority of infected individuals. Similar reactions to retroviral infection are also seen in animal models. A possible role for the newly described human retrovirus-5 (HRV-5) is discussed, though current evidence does not support a role in Sjogren\'s syndrome. Other autoimmune diseases are under investigation.