Calendula officinalis is a member of the richest family of flowering plants, Asteraceae. In this study, the volatile profile of C. officinalis flowers obtained from the Marmara region was determined using SPME-GC/MS-O technique. Antimicrobial effects of essential oil in the C. officinalis flowers against Gram negative and Gram positive bacteria and yeast were determined by disc diffusion method (0.6 mm disc diameter). Six different concentrations (10-200 mu g/mu L) were studied for the determination of minimum inhibitory concentration. 22 aroma active compounds were identified in the sample of the GC/MS-Olfactometer. Antimicrobial activity was tested against both Gram negative and Gram positive bacteria using essential oil of C. officinalis flowers. As a result, it was found that essential oils of C. officinalis flower had high antimicrobial activity. A total of 21 main essential oils were found in C. officinalis flowers.