The unionid freshwater mussel Nitia teretiuscula (Philippi, 1847) was collected from the River Nile at Sohag Governorate. Both the spatial and temporal distributions were investigated using a systematic sampling technique. In addition, the inter-relationships between the abundance of the studied species and some measured environmental factors was examined. The abundance of the mussel fluctuated during most of the year and showed clear favoring for the shallow area near the bank of the river. The organic content of the sediment was the most effective environmental factor on the mussel distribution. The present species showed also a new dispersal phenomenon that is recorded for the first time in family Unionidae. The individuals release many gelatinous structures, named embryophores, that possess many cone-shaped arms that help in carrying early stages away by water currents.