Conditions of interferon production stimulation were studied in human tonsillar cell cultures exposed to natural and synthetic inducers : poly(I) . poly(C), phage f2 RNA replicase, phytohemagglutinin and the low-molecular inducer gossypol (beta-aminoethyl sulfoxide Na). It has been shown that being inferior in the productivity per one cell to the continuous lymphoblastoid Raji and Namalva cell liness the tonsillar cell cultures, due to their high density, produce rather high interferon titers reaching hundreds of IU50/ml. The viability of the tonsillar cell cultures and their incubation at 37 degrees C during 24 hours are rather important for adequate interferon production.