This study was focused on determining the manganese (Mn) concentration in vegetative organs of 10 plant species (8 woody and 2 herbaceous), from four sites in the protected natural resource Kosmaj. The concentration of Mn was analyzed at the beginning of the vegetation period, during a two-year period (2012-2013). The results indicate a wide range of Mn concentrations, depending on site and plant species. [Projekat Ministarstva nauke Republike Srbije, br. 31041: Establishment of Wood Plantations Intended for Afforestation of Serbia]