Influence of different hydrodistillation conditions were evaluated from the standpoint of oil yield and composition of essential oils from the seeds of three varieties ofFoeniculum vulgareMill. Three hydrodistillation methods and three degrees of seed grinding were considered. Chemical composition of essential oils was determined by GC and GC/MS. The main constituents of the oils were: trans-anethole (81.8–91.1%), limonene (1.0–6.7%), fenchone (1.3–10.2%) and methyl chavicol (1.5–3.9%). Both the method of distillation and the degree of seed grinding showed significant effects on the yield and quantitative composition of essential oils.