The diagnosis of Sjogren's syndrome (SJ) as an underlying disease of keratoconjunctivitis sicca is important because of the many ocular and systemic complications. We compared the results of impression cytology of conjunctiva (ICC) and the results of labial salivary gland biopsy (LSB) with impression cytology of buccal mucosa (ICB) in 33 patients with SJ. LSB, ICC, and ICB were considered positive in all patients. Moderate to severe changes were graded in 85% of the biopsy specimens, 94% of the conjunctival specimens, and 76% of the buccal mucosa specimens. The rate of agreement between LSB and ICB was 97%. The use of ICB in the clinical ophthalmological examination may be helpful in patients with consistent history, and clinical and ocular findings, before the biopsy procedure.