Staphylinidae (including Silphinae) is the largest family in the world with approximately 67,000 species, including one extinct and 34 extant subfamilies. Of the 34 subfamilies within this family, Aleocharinae has the largest number of species. Aleocharinae has over 1000 genera and over 12,000 species and is the subfamily with the most species associated with the mushrooms. This field study collected Aleocharinae species from mushrooms in Belgrad Forest. A total of 11 species belonging to three genera in Aleocharinae were collected and identified. Distribution graphs of the species according to months, regions of Turkey, neighboring countries and zoogeographic regions are provided. The number of individuals and the taxonomic diversity of the collected species were assessed using the Brillouin diversity index by PAST 3.15 program, and UPGMA similarity analyses were conducted to evaluate the collected species in relation to Turkey, neighboring countries, and zoogeographic regions using MVSP 3.22 program. This study, which was planned to start with the Belgrad Forest selected as the pilot region, will be expanded to other regions in the future.