Homogenates of lymph node and skin biopsy specimens and lymphocyte suspensions from patients with sarcoidosis and control subjects were injected into the footpads of CBA/J mice; histologic response was examined at intervals of 15 to 360 days. Kveim tests and complete autopsies were performed on animals of each group. Granulomas or equivocal granulomas were observed in 14.8% of biopsy specimens from animals that received sarcoid tissue homogenates and in 14.8% of control animals. No granulomas were observed after injection of lymphocytes from patients with sarcoidosis or from control subjects. Kveim tests were negative in all animals and autopsies were unremarkable. These studies fail to confirm previous reports of a "transmissible agent" in sarcoidosis and demonstrate that by the use of these techniques, such an agent is not invariably present in sarcoid granulomas.