Abstract Distillation of fresh fowering tops of Nepeta sibirica L., yielded 1.0% light yellow mobile oil. GC and GC/MS analysis of the oil composition revealed that the major components were neoepinepetalactone (78.8%) and germacrene D (9.4%), representing 88.2% of the total oil. Key Word Index: Nepeta sibirica Lamiaceaeessential oil compositionneoepinepetalactone