abstract the chemical composition of the essential oil of spontaneous rosmarinus officinalis from greece was analyzed by gc and gc/ms and tested for its antifungal activity against five phytopathogenic fungi (sclerotinia sclerotiorum, phytophthora nicotianae, sclerotium cepivorum, fusarium oxysporum f. sp. dianthi and fusarium proliferatum). thirty-seven components compounds representing 97.3% of the total oil were identified. the major constituents were -pinene (24.1%), camphor (14.9%), 1,8-cineole (9.3%), camphene (8.9%), -terpineol (8.8%) and borneol (8.0%). the most sensitive fungus was ph. nicotianae, followed by s. sclerotiorum, s. cepivorum, f. proliferatum and f. oxysporum f. sp. dianthi.