Abstract Because of its sensitivity to cold, rosemary was not previously cultivated in Hungary. As a result of the selection work, we have been successful in isolating a frost-resistant selection of rosemary, the cultivation of which is now underway. The composition of the oil of this new rosemary selection is slightly different to other rosemary oils. The major components of the oil were Î±-pinene (4.1â14.4%), 3-octanone (trace-10.0%), Î²-pinene (5.3â13.7%), 1,8-cineole (21.3â46.4%), camphor (13.0â31.0%) and verbenone (2.5â11.1%). Among the components identified by GC and GC/MS, 3-octanone and verbenone were found to be the characteristic constituents of the oil of the new Hungarian selection. It was also found to possess antimicrobial activity. Key Word Index: Rosmarinus officinalis Lamiaceaerosemaryfrost-resistanceessential oil compositionÎ±-pinene3-octanone1,8-cineolecamphorverbenoneantimicrobial activity