Approximately 4000 lines (cultivars, introductions, breeding lines, and radiation-induced mutants) of cultivated peanuts (Arachis hypogaea L.) were tested for resistance to peanut stunt virus (PSV), and all were susceptible to PSV infection. Twenty-one lines were less severely damaged than the others. In addition, 90 collections of wild Arachis species including 55 members of section Rhizomatosae, 17 of Arachis, 16 of Erectoides, and one each of Caulorhizae and Extranervosae were tested. Several collections in sections Arachis, Caulorhizae, Erectoides and Rhizomatosae were highly resistant to PSV. Collections of A. duranensis, A. villosa, and a hybrid derivative of A. villosa-A. correntina have the most immediate potential for utilization. The reactions of a few F1 hybrids of Arachis species indicated that resistance to peanut stunt virus is not conditioned by a single dominant gene. Resistance of wild species could be used to develop resistant cultivars.