Sixty dogs with chronic keratoconjunctivitis sicca were treated by topical administration of 2% cyclosporine twice daily. Causes and duration of keratoconjunctivitis varied. Tear production improved in 75 of 100 eyes, and corneal pigmentation decreased in 45 of 67 eyes. Six factors were evaluated to determine their influence on treatment outcome. The only significant variable was the initial Schirmer tear test value. Side effects were few. Evidence of burning in response to application of cyclosporine resolved with change in the formulation of the topical solution.