Abstract: The object is to provide a novel organism identification method which can be used as an alternative method to a conventional organism identification method which utilizes DNA and requires enormous labor. Developed is an organism identification method for determining whether or not an organism of interest is identical to a specific organism or a progeny thereof, which is characterized by introducing a DNA tag(s) in advance into a cell(s) of the specific organism, or a parasite or a symbiont with the specific organism, and determining whether or not the organism of interest is identical to the specific organism or a progenitor thereof based on the detection or non-detection of the DNA tag in DNA extracted from the organism of interest, or the parasite or the symbiont with the organism of interest.