the essential oils (eo) extracted by hydrodistillation from the leaves of walnut cultivated in the region of mateur (north of tunisia) have shown that essential oils yield ranging from 0.033% to 0.075%. the analysis by gc-fid and gc-ms identified twenty-nine compounds representing 84.25% of total oil. the major constituents were caryophyllene oxide (16.9 to 27.4%) followed by -caryophyllene (4.0 to 22.5%), germacrene (1.2 to 9.4%) and - pinene (2.8 to 9.5%). the essential oils from juglans regia l.' leaves were rich in sesquiterpene hydrocarbon (13.9 to 39.6%), oxygenated sesquiterpenes (16.9 to 27.4%) and alcohols (7.6 to 27.8). the differences in the chemical composition and class might have been derived from varieties, wish have confirmed by statistical analysis. in fact, pca and hca analyses show a good discrimination between varieties.