Trachea, lung, liver, spleen, pancreas and brain of 77 heman patients who had died in the course of clinically diagnosed influenza were subjected to virological and histopathological examination. Type A influenza viruses closely related to the virus variants contemporarily in circulation were isolated from 12 of the lethal cases. In 10 of them, virus was demonstrated in organs other than respiratory, most often the brain. Influenza antigen was also demonstrated in brain tissue by immunofluorescence.