Abstract The essential oil content and their chemical composition of herb, fowering and mature umbels of wild carrot growing in Poland (Daucus carota L. ssp. carota) as well as cultivated carrot seed oils were examined. The qualitative and quantitative analyses of the essential oils were performed using GC and GC/MS methods, and the results are given for the 1999 season. Generally, oils obtained from different parts of wild carrot plant consisted mainly of monoterpene hydrocarbons (72â84%), whereas the main compounds of the oil of cultivated carrot breeds (var. Koral and Perfekcja) were oxygenated sesquiterpenes (51% and 44%, respectively). A commercial sample of carrot seed oil available on the Polish market was also examined; monoterpenes were the main compounds (64% of the total oil). Antimicrobial properties of the oils obtained were compared using four species of bacteria and two species of fungi. The MICs were determined by the agar dilution method. The oils obtained from cultivated carrot seed were more effective against all tested organisms. The strongest overall activity was demonstrated by the commercial oil of cultivated carrot seeds.