In a prospective study of systemic sarcoidosis, 28 patients underwent 55 conjunctival biopsies. The incidences of positive granulomatous lesions in proven and suspected sarcoidosis cases were 71.4% (ten of 14 patients) and 28.5% (four of 14 patients), respectively. Thus, random, bilateral conjunctival biopsies should be performed as soon as possible in all cases of presumed sarcoidosis.