An Aspidogastrean parasite Rohdella anodontiase sp. nov. "is recorded for the first time from the fresh ater~ mussel, Ahodonta rubens, It is found in the preicardial and nephridial cavities of the mussel which are collected from the River Nile at Sohag governorate, Egypt. The present 'parasite has it's own diagnosatic charactes by which it is considered as new species belonging to the genus Rohdella, suberfamily Rohdellinae. Such cheracters are its measuremehts are different from those of the other known species of the same genus.