Tricholoma matsutake is among the most valuable mushrooms in the world, and natural populations of this species from different geographic regions are priced very differently. To examine the geographic origins of 'matsutake' mushrooms traded in China, we analyzed the mushrooms from two major production and trading regions in China, the Southwest and the Northeast, using a recently published retroelement-based DNA marker. Our analyses showed that 67% of commercial matsutake claimed to be from the northeast were in fact genetically identical to those from the southwest but were different from authentic northeast samples. The finding suggests that caution should be applied to the authentication of commercial matsutake from northeast China.