A comparison was carried out for the Km and maximal rates of conversion on (Vmax) with primers containing noncomplementary bases, as well as primers without several bases, and fully complementary primers of the same length. The number of complementary bases from the 3' end to the noncomplementary nucleotide was shown to determine the efficiency of interaction (and conversion) of the primers containing noncomplementary bases with enzyme. The DNA polymerase practically does not discriminate between the primers without one or two bases and the fully complementary primers. Elimination of one base in any position from the 3' end of the primer is equivalent to shortening of the primer by one nucleotide unit, and leads to a decrease in the affinity by a factor of 1.8. We suppose that DNA polymerase does not participate in primer mistake correction during the repair process if the DNA contains apurinic or apyrimidinic nucleotide units.