Abstract The two essential oils isolated from plants of hyssop (Hyssopus officinalis L. ssp. officinalis) grown in two different localities near Urbino (Marche, Italy) were analyzed by GC and GC/MS. The major components were pinocamphone (34% and 18.5%), isopinocamphone (3.2% and 29%) and Î²-pinene (10.5% and 10.8%). The major differences in the composition of the oils were detectable in the ratio of pinocamphone/isopinocamphone, in the percentage of linalool (0.2% and 7.9%) and camphor (0.3% and 5.3%). The oils showed antifungal activity against 13 strains of phytopathogenic fungi; the activity of the oil extracted from plants grown at 1000 m above sea level showed higher activity.