Aim. Study of the new synthetic asymmetrically-substituted porphyrins antiviral properties with the use of bacteriophages as model viruses. Materials and methods. In this work the ability of 5,10,15-tri(N-methyl-4-pyridyl)-20-(n-nonyl) porphyrin free base and its zinc complex to inhibit staphylococcal phage, phage T4 and T7 activity had been studied. Bacteriophages were incubated in presence of studied porphyrins in the dark and during irradiation, and then plated using the standard double-layer method. Final porphyrin concentrations were 0,1 μМ, 1 μМ and 10 μМ. Porphyrin absorption spectra were recorded after incubation with phage suspension with spectrophotometer “Spekol-10” and then were digitized. Results. It was shown, that staphylococcal phage is more sensible to the porphyrin action. Porphyrin free base suppress its activity on 68% in the dark and 80% after photoactivation. Phage inactivation with porphyrin zinc complex reached up to 100% in the dark and after irradiation. Phage Т4 is more sensible to the porphyrins action in the dark. Decrease of the phage activity in the dark reached up to 68% in presence of porphyrin free base, and 88% in presence of porphyrin zinc complex, and 24% and 35%, respectively, after photoactivation. Inversely, phage Т7 is more sensible to the photoactivated compounds action. Decrease of its activity in the dark reached up 21% in presence of porphyrin free base, and 16% in presence of porphyrin zinc complex, and 28% and 53%, respectively, after irradiation. Spectroscopic studies show that studied porphyrins bind to the phage nucleoproteins. Conclusion. Synthetic asymmetrically-substituted porphyrins affect the studied bacteriophage activity due to complex formation with phage particles.