Chinese yam (Dioscorea polystachya) has been cultivated as a food crop in Japan. The blue mold disease of Chinese yam during the storage and treatment of forced sprouting is one of the hindrances in attaining productivity that can lead to food security in tropical countries and steady farming that will eventually lead to farmers' profitability. In this study, three species of the genus Penicillium related to the blue mold of yam were isolated from two locations in Hokkaido, Japan. From the morphology and phylogeny, these were Penicillium albocoremium, P. polonicum, and P. sclerotigenum. Pathogenicity was confirmed in all Penicillium-like isolates, and sensitivity against benomyl was evaluated based on MIC. The first two species were newly recorded as the causal fungi of the blue mold of yam in Japan, and the pathogenicity of P. albocoremium is first confirmed in yam seed tuber. Moreover, some isolates showed possible resistance to benomyl.