A virus isolated from a peanut plant showing chlorotic spot symptoms that was collected at Kalasin, North East Thailand in 1979, was identified as peanut mottle virus based on host range, symptomatology, aphid transmissibility, particle morphology, serological relationships, etc. The virus was transmitted by sap inoculation and by aphid, but not through seed of peanut from Japan. The virus infected 14 plant species in four families and infected systemically peanut, pea, broad bean, soybean, etc. with visible symptoms. It also produced local lesions on inoculated leaves of Top Crop bean. Thermal inactivation point, dilution end point and longevity in vitro of the virus were 55-60°C (10 min), 10^-4-10^-5, and 7-14 days (20°C), respectively. The virus consisted of filamentous flexuous particles, 700-725 nm in length. The virus was purified from infected pea plants, and the yield of purified virus was about 0. 76 mg from 100 g plant materials. The virus reacted positively with antiserum to peanut mottle virus from Japan.