The rotifer communities were determined in El-rayah El-Nasery and El-rayah El-Tawfeky (Egypt) as small branches of River Nile by tracking seasonally variations in diversity and population density. It was found that the annual density of rotifers in El-Rayah El-Nasery (5442000 Ind. /m³) was higher than that in El-Rayah El-Tawfeky (3680000 Ind./m³).The highest density of rotifer occurring in spring season but the lowest density occurring in winter season in the two rayahs. A total of 40 rotifer species were identified in the present study. The highest number of species and richness was observed in summer and the lowest number and richness was recorded in winter season. Of these species, Prolides sp, Keratella cochlearis ,k. tropica,  Brachionus calyciflorus, B. caudatus, Polyarthra vulgaris,  Philodina roseolaand Tricocerca pusilla were abundant.