In this study of MUC1 in dry eye disease, we characterize the expression of MUC1 in Sjogren’s syndrome dry eye as compared with aqueous deficient (KCS) dry eye and non dry-eyed (NDE) controls, to gain further insight into the role that MUC1 may play in dry eye disease. The gene discussed is MUC1; the disease is Keratoconjunctivitis sicca.