Anti-Kveim-antigen serum was obtained by immunizing rabbits with Kveim antigen from lymph nodes and spleen in complete Freund's adjuvant. In the Ouchterlony test and in counter-immuno electrophoresis, a precipitation band with Kveim antigen from spleen and lymph nodes was demonstrated after absorption of the antiserum with serum and extracts of normal lymph nodes and spleen.