A total of 81 isolates of Penicillium were isolated from postharvest seeds of barely, Job’s-tears, maize, sorghum and rice from 1997 to 2003. Based on the morphological characteristics, they were identified as P. chrysogenum, P. citrinum, P. cyclopium, P. oxalicum, P. polonicum, P. purpurogenum and P. viridicatum. P. chrysogenum was detected from Job’s-tears, rice and sorghum seeds, P. citrinum from maize seeds, P. cyclopium from sorghum seeds, P. oxalicum from barely, maize, sorghum and rice seeds, P. purpurgenum from maize, rice, sorghum seeds, P. viridicatum from Job’s-tears, maize and rice seeds, P. polonicum from Job’s-tears, maize, rice and sorghum seeds. Among these species, P. cyclopium, P. polonicum and P. purpurogenum were first reported in Korea. Especilally, about 50% of the Penicillium isolates detected from the seeds were P. polonicum. Identification of the Penicillium species using morphological characteristics was difficult especially for the species belonging to the subgenus Penicillium such as P. polonicum.