Resumo. The natural range of the Mixed Ombrophilous Forest (MOF) is located in the southern Brazilian highlands. The Mixed Ombrophilous Forest is characterized by the presence of Faxinal People, who live in Caboclo communities, characterized by their community life. This study aimed to analyze and compare the floristic diversity, the horizontal structure and diametric distribution of the Mixed Ombrophilous Forest (MOF) in Faxinal System in localities of Marmeleiro de Baixo and Marmeleiro de Cima, situated in the city of Rebouças/PR ¿ Brazil. Thus, two permanent sampling units were installed, employing an area of 1 HA (100 m x 100 m each), where all trees with DBH (diameter at breast height) exceeding 10 cm were measured. In Faxinal Marmeleiro de Baixo, 352 individuals were inventoried, belonging to 36 species, 24 genera, distributed in 16 families, whereas in Faxinal Marmeleiro de Cima, 445 individuals were inventoried, pertaining to 22 species, 18 genera, distributed in 11 families. The species with highest importance value in Faxinal Marmeleiro de Baixo were Mosiera prismatica (26.46%) and Campomanesia xanthocarpa (7.67%), while in Faxinal Marmeleiro de Cima they were Casearia obliqua (28.59%) and Capsicodendron dinisii (13.27%). Taking into account the results of this study, it can be concluded that historical (phytophisiognomy) and ecological factors (the area of the fragments and the occurrence of anthropic disturbances) represent important elements that characterize the composition and richness of species in forest fragments using the forest under a Faxinal System.