Improving the forage quality and balance of their minerals in rangeland ecosystems is important for rangeland managers to improve livestock productivity (Mohamed et al. 2003; Epstein and Bloom 2005). This research investigated the amount of several minerals; Calcium (Ca), Phosphorus (P), Potassium (K) and Magnesium (Mg), in some important species of Leguminosae including Medicago sativa, Trifolium repens, Trifolium pratense and Lathyrus pratensis, that are grazed by livestock in the Bandar Torkaman plain rangelands in north of Iran