Abstract No correlation was found between ultramicroscopic cytoplasmic tubuloreticular structures in circulating lymphocytes and Epstein-Barr (E.B.) virus antibody in a group of patients with connective-tissue disease. E.B. virus antibody titres were not greater than in controls. The combined approach used in this study fails to provide supportive evidence that E.B. virus is a causative agent in the connective-tissue diseases.