Various plant species, as many as 145 species in 43 families, were tested for susceptibility to the ordinary strain of the cucumber nosaic virus for two years from 1973 to 1974. Inoculations were made by mechanical method using carborundum. Plants in 71 species belonging to 27 families were infected. Of these species, systemic mosaic developed on the new leaves of plants in 57 species belonging to 24 families. Twenty-four species of plants, previously not reported as hosts of the CMV, were found to be infected in this experiment. These are Stellaria aquatica, Achyrauthes japonica, Agerratum houstonianum, Centipeda minima, Gillardia pulchella, Henisteptalyrate, Ixeris dentata, Saussurea uchiyamana, Brassica campestris, Lepidiumapetalum, Lobelia chinensis, Chenopodium bryoniaefolium, Carex neofilipes, Acalypha austalis, Amphicarpaea edgeworthii, Lotus corniculatus var japonicus, Phaseolus angularis, Sedum aizoom var heterodontum, Mosla punctulata, Perilla frutescens var japonica, Teucrium japonicum,. Linum usitatissimum, Mazus japonicus, Verbena hybrida. Twenty-three species reported to be susceptible by previous workers, but negative results were obtained in our experiment with Allium cepa, Celosia cristat, Daucus carota var. sativa, Artemisia asiatica, Callistenphus chinensis, Erigeron canadensis, Helianthusannuus, Tagetes eracta, Impatiens balsamina, Raphanus sativus, Ipomea batatas, Glycine max, Phaseolus vulgaris, Lilium longifolium, Papaver gomniferum, Sorghum vulgare, Triticum aestivum, Zea mays, Rumex coreanus, Potulaca grandiflora.