abstract the composition of the oils from flowers of three iranian achillea species (a. tenuifolia lam, a. biebersteinii afan., a. filipendulina lam.) were collected during the flowering period. the essential oils obtained by steam distillation. the percentage of all three oils were 0.20% v/w calculated on the dry weight, analyzed by gc and gc/ms, all three oils consisted mainly of monoterpenes. the major constituents of a.tenuifolia were -muurolene(13.3%), -pinene(10.0%), camphor(9.4%), p-cymene(8.5%), and tras-carveol(8.4%), and a.biebersteinii were piperitone (45.9%), l,8-cineole(17.6%), limonene(5.6%) and p-cymene(5.2%), a. filipendulina were limonene (26.79%), carvacrol(9.3%), l,8-cineole(8.7%), borneol(7.8%) and -humulene (5.6%).