Mycotoxin producing moulds are commonly in contact with forage in the field before harvest, during harvesting, drying and transport and during storage. Therefore, this study was to isolate and identify fungi contaminated rice straw in the earlier spring of Korea. The pure fungi colony was isolated from normal rice straws in the tree dairy farms. The fungi were cultured on MEA and PDA agar plate and confirmed by sequencing the ITS region. Fungal contamination was found in all samples of rice straws and mold counts averaged 4.6×10⁴ per gram. The mycotoxigenic fungi found were Penicillium roqueforti and Fusarium culmorum. Other several fungi were determined Gibberella moniliformis, Ascomycota sp., Myrothecium sp. When the rice straw samples were analyzed mycotoxins by HPLC, it was not found aflatoxins, zearalenone, deoxynivalenol, fumonisin, ochratoxins A and T-2 toxin. The results suggest t㏊t the mold contaminated rice straw is not activated in the spring of cool season but is able to develop in the coming warm and humidly summer, specially mycotoxigenic fungi such ase Penicillium roqueforti and Fusarium culmorum.