The present paper is an overview of studying of DNA-porphyrin interactions using viscometry in combination with the spectroscopic methods. It was shown, that when porphyrins interact with DNA as an outside binder, the interaction mode and intensity does not depend on metal center, peripheral substituent’s and their positions on pyridylic ring. In case of planar porphyrins, the binding type is mainly determined by type of peripheral substituent’s and their position on the pyridylic ring. Currently, viscometry is widely used to study the interaction of porphyrins with DNA as an adjunct to other methods. Due to high accuracy and maximum sensitivity to changes in the size and shape of macromolecules, it is recommended to use viscometry as the cogent method for studying the interaction of small molecules with DNA, especially if intercalation is expected using other methods if necessary to confirm the results obtained.AbbreviationsDNAdeoxyribonucleic acidH2TAllPyP4meso-tetra-(4N-allylpyridyl) porphyrinH2TAllPyP3meso-tetra-(3N-allylpyridyl) porphyrinH2THOEtPyP4meso-tetra-(4N-hydroxyethylpyridyl) porphyrinH2THOEtPyP3meso-tetra-(3N-hydroxyethylpyridyl) porphyrinUV/VIS spectrophotometryultraviolet-visible spectrophotometryCD spectroscopycircular dichroism spectroscopyCommunicated by Ramaswamy H. Sarma