We have studied the changes in the serum level of the following cytokines during the course of treatment of nosocomial pneumonia (NP): pro-inflammatory--IL-1alpha and IL-6, chemoattractive--IL-8, anti-inflammatory--IL-4 and IL-10, and differentiating-activating--IFN-gamma and TNF-alpha. It has been found that at the time of admission of the patients the clinical severity of their condition was correlated with increased levels of all circulating cytokines except for IFN-gamma, the level of which was low. An adequate ethiotropic therapy helped to clear the clinical symptoms of infection and intoxication in 1-2 weeks. The level of circulating pro- and anti-inflammatory cytokines, IL-8, and TNF-alpha was decreasing, however, the level of IFN-gamma did not change significantly during 15 days. The ratio IFN-gamma/IL-10 did not change much but was slightly low during the treatment of the severe form of NP. Radical positive changes in the cytokine dynamics were achieved after the addition of leukinferon to the ethiotropic therapy.