1. The present paper deals with Penicillium rots of Satsuma orange (Citrus unshiu), which occur in storage or transit. 2. As the fungi causing the rots were found P. italicum, P. digitatum, P. expasum and P. n. sp.; their occurrence being estimated at 89% for P. italicum, 73% for P. digitatum, 0.9% for P. expansum and at 28% for P. n. sp. 3. Among those four Penicillia, P. italicum and P. digitatum are parasitic on citrus fruits but others are able to attack citrus, apple, pear, persimon and grapes. 4. As the method of control are recommended the fruits immersion in two to five per cent of borax solution for five to seven minutes. 5. For Penicillium n. sp. causing citrus rot, P. fructigenum is proposed; its characters are briefly described as follows : (snip)