Host-plant resistance in alfalfa (Medicago sativa L.) is insufficient for control of the alfalfa weevil (Hypera postica) or the potato leafhopper (Empoasca fabae), two of the most important insect pests of alfalfa. Some wild Medicago species, which have erect glandular hairs, possess adequate host-plant resistance for control of both pests. We established a field trial (Wymore silty clay loam) in 1985 to determine the effects of erect glandular hairs on forage quality of several perennial Medicago species. Glandular and eglandular (without erect glandular hairs) plant populations were selected from the diploids, M. prostrata Jacq. and M. glandulosa David, and the tetraploids, M. glutinosa Bieb., M. sativa × M. glutinosa, and M. sativa × M. prostrata. Eglandular M. sativa ’Riley’ and M. sativa subsp. caerulea (Less, ex Ledeb.) Schmalh. were included as controls. Foliar diseases and insects were controlled. Leaves and stems were separated for three harvests in 1985 and one in 1986. The presence of erect glandular hairs did not significantly affect concentrations of neutral or acid detergent fibers, hemicellulose, lignin, or cellulose of leaves or stems within the species or hybrids tested. Neutral and acid detergent fibers and cellulose concentrations were generally lower in stems and higher in leaves of diploids than in corresponding parts of the tetraploid alfalfa cultivar Riley.