Abstract: Unionicola aegyptiaca was described for the first time from the freshwater mussel, Caelatura aegyptiaca, River Nile, Sohag, Egypt. The descriptive characters of the present species are in accordance with those of the superfamily, family and the genus. The present species has a specific characters compared with characters of other species of the same genus. These characters are summarized as follows: four dorsal plates, two pairs of platelets, nine pairs of dorsal setae in female and eleven pairs in male, two pairs of small plates, 5 pairs of genital setae in female and 4 pairs in male and 25 pairs of genital acetabulae.