Polyelectrolytes currently play an increasingly important role in antivirus therapy. Antiviral activity towards influenza virus, measles virus, herpes simplex virus type 1, and cytomegalovirus was demonstrated for the 6000 Da polyelectrolyte polyallylamine. A nontoxic polyallylamine concentration of 30 µM at which the compound retains its antiviral effect towards measles and influenza viruses but lacks any toxic effect on human cells was previously determined. It is well known, at the same time, that simultaneous virus exposure to physical environmental factors and chemical substances causes a more significant decrease in virus infectivity. Temperature is among these physical factors since thermal exposure causes virus inactivation. Analysis of virus thermal inactivation parameters is of high practical importance when it comes to the development of vaccines against influenza virus and to the study of how virus particles infectivity decreases on various surfaces. In this view, the study of kinetic and thermodynamical characteristics of influenza virus thermal inactivation in the presence of the antiviral preparation polyallylanime is of particular interest. The paper reports that thermal inactivation of influenza virus in the temperature range of 38-60°C in the presence of polyallylamine follows the first-order reaction kinetics. Thermodynamic parameters of influenza virus thermal inactivation evidence that influenza virus surface proteins are involved in the inactivation process as a result of their interaction with polyallylamine. The obtained results show that polyallylamine may be used to accelerate thermal inactivation of the influenza virus.