The volatile compounds of Trifolium (Leguminosae) echinatum L., Trifolium stellatum var. stellatum L., Trifolium nigrescens subs. petrisavi (Celm) Holmboe, Medicago polymorpha var. vulgaris L., Medicago arabica (L.) Huds. and Medicago minima var. minima (L.) Grufbg. were obtained by hydrodistillation in a Clevenger-type apparatus, and then analyzed by gas chromatography-mass spectrometry (GC-MS) methods. In total, seventy-one constituents (terpenoids, alcohols, ketones, aldehydes, esters, hydrocarbons, fatty acids and benzene compounds) were identified from Trifolium oils and Medicago oils. According to the chemical class distribution of the oils of Trifolium and Medicago species, the fatty acids (29.7 - 63.4 % and 61.9 - 83.7 %, respectively) are the most abundant class of volatile compounds of three Trifolium and Medicago species. The present work is the first report on these plants oil composition.