Cylindrocarpon musae sp.nov., present in burrowing nematode lesions on bananas, is described. It has been found in root and rhizome lesions in Honduras, Costa Rica, Panama, Colombia, Ecuador, Philippine Islands, Martinique, and Guadeloupe. It comprises from 15 to 50% of the fungus colonies isolated from these lesions. C. musae has probably moved worldwide with the vegetatively propagated banana and is likely present wherever Radopholus similis occurs on bananas. C. musae is a good wound invader and could be important in the pathology of root and rhizome rot caused by the burrowing nematode.