Keratoconjunctivitis sicca is a common ophtalmic problem in dogs. The condition usually results from a deficiency of the aqueous component of the precorneal tear film. A deficiency in the aqueous portion of the tear film results in an increase in tear film osmolality, conjunctivitis and keratitis and secondary corneal ulcerations. Although the cause of the keratoconjunctivitis sicca in dogs can not be determined, circumstantial evidence, histopathologic lesions, and circulating autoantibodies suggest that autoimmune processes account for the majority of cases. The diagnosis of keratoconjunctivitis sicca is based on clinical signs and results of a Schirmer tear test. The hallmark clinical sign is a mucoid to mucopurulent ocular discharge that adheres to the corneal epithelium and is usually accompanied by a cojunctival redness. The Schirmer tear test is a semiquantitative method of assessing tear function. Normal dogs wet 14-24 mm/min on Schirmer tear test but keratoconjunctivitis sicca cases typically wet less than 8-10 mm/min. Keratoconjunctivitis sicca is nearly always misdiagnosed as primary bacterial or nonspesific conjunctivitis or keratitis because clinical signs are similar. The conventional therapy in dogs with keratoconjunctivitis sicca consist of frequent typical applications of such medications as artificial tear replacement solutions, parasympathomimetic agents, antiinflammatory drugs, mucolytics, and antibiotics. Recently, keratoconjunctivitis sicca therapy has been radically altered by the introduction of a single topical agent, cyclosporine. Cyclosporine is an immunosuppressant useful in organ transplantation. Topical cyclosporine, used once or twice daily, can stimulate tear production and alleviate many of the signs of the disease.