In a series of 750 patients, 311 of whom were eventually found to have sarcoidosis, the intracutaneous Kveim test proved to be an important aid in the early and accurate diagnosis of sarcoidosis. The sarcoidal tissue, preferably spleen, is obtained aseptically; the suspension is heattreated and preserved with phenol. With validated sarcoidal tissue suspensions, positive microscopic reactions consisting of granuloma formation at the injection site after 4 to 6 weeks were observed in 84% of patients with biopsy-confirmed sarcoidosis. Two patients among a group of 303 patients with diseases other than sarcoidosis showed false-positive reactions. The widespread application of the Kveim test has been hampered by inadequate supplies of properly screened Kveim suspensions and by the need for acquiring some experience in the microscopic reading of the biopsied test-site.