A fruit soft rot caused by Mucor piriformis occurred on sweet persimmon storages in Jinju, Changwon and Gimhae, Gyeongnam province, Korea, 2003. The disease infection usually started from wounding after cracking of fruits. At first, the lesions started with water soaked and rapidly softened and diseased lesion gradually expanded. Colonies on potato dextrose agar at $20^{circ}C$ were whitish to olivaceous-buff Sporangia were globose, black and $96{sim}153{mu}m$ in size. Sporangiophores were $26{sim}42{mu}m$ in width. Sporangiospores were ellipsoid and $5.8{sim}10.6{ imes}4.3{sim}7.6{mu}m$ in size. Columella was obovoid, cylindrical-ellipsoidal, pyriform, subglobose and $80{sim}125{mu}m$ in size. Optimal temperature for mycelial growth was $20^{circ}C$ on PDA. The causal organism was identified as M. piriformis. This is the first report of fruit soft rot on sweet persimmon caused by M. piriformis in Korea.