Abstract The essential oils isolated by hydrodistillation from trunk bark and leaves of Talauma ovata A. St. Hil. (Magnoliaceae), collected in four seasons, were analyzed by capillary GC and GC/MS. Altogether 52 components were identified. The oils were characterized by predominance of cyclic sesquiterpenes. The main components were linalool, trans-Î²-guaiene, germacrene D, germacrene B, spathulenol, caryophyllene oxide, viridiflorol and Î±-eudesmol. The content of individual components was variable during the year. All oils were screened against several strains of bacteria and yeasts, using the agar well-diffusion technique. The antimicrobial activity of oils showed strong dependence with the season. Significant activity was found for oils obtained in the spring and summer.