Ten patients with Boeck's sarcoid were tested with lepromin. Negative tests were obtained in seven and positive ones in three. Six of the seven negative tests were in patients known to have negative tuberculin tests, and two of the three positive were in patients with positive tuberculins. Two patients with active tuberculosis gave positive lepromin tests. Apparently patients with positive tuberculin tests give false positive tests with lepromin. No evidence was obtained to indicate that Boeck's sarcoid is an attenuated or modified form of leprosy.