Poly(ADP-ribosyl)ation (PARylation) of proteins is one of the immediate cell responses to DNA damage and is catalyzed by poly(ADP-ribose) polymerases (PARPs). When bound to damaged DNA, some members of the PARP family are activated and use NAD⁺ as a source of ADP to catalyze synthesis of poly(ADP-ribose) (PAR) covalently attached to a target protein. PAR synthesis is considered as a mechanism that provides a local signal of DNA damage and modulates protein functions in response to genotoxic agents. PARP1 is the best-studied protein of the PARP family and is widely known аs a regulator of repair of damaged bases and single-strand nicks. Data are accumulating that PARP1 is additionally involved in double-strand break repair and nucleotide excision repair. The review summarizes the literature data on the role that PARP1 and PARylation play in DNA repair and particularly in base excision repair; original data obtained in our lab are considered in more detail.