To provide a method for clearly detecting genetic polymorphisms at several positions, especially the genetic polymorphisms at several positions such as cytochromes 2D6 and 2C19 in good repeatability; and to provide a reagent therefor.

The method for detecting the genetic polymorphisms by carrying out the amplification by using at least one of a wild oligonucleotide for detection and a variant oligonucleotide for detection, and a nucleic acid-specific label is characterized by detection of sequences at least at two different variant positions by the same amplification condition.