This article compares the mycorrhization of the roots of 2 grass species ( Agrostis capillaris and Deschampsia cespitosa ) inhabiting the overgrown sand quarry in the Leningrad region. The purpose of the article is to analyze the dynamics of mycorrhization of these species during the transition from the early stage of overgrowth to the advanced one. Plant communities belonging to the first two stages of overgrowth have been identified and described. On the basis of microscopic examination, it was established that in the roots of all species there is arbuscular mycorrhiza in the form of non-septic mycelium, arbuscules and vesicles. The authors come to the conclusion that, despite the increased role of grasses in the communities of the more advanced stage of succession, only Deschampsia cespitosa has a significant increase in mycorrhization parameters as compared to the early stage of succession.