The present study includes natural spawning of Nile tilapia (Oreochromis niloticus) under different levels of water temperature and rearing of fry at different stocking densities of Nile tilapia (Oreochromis &atlas^.). The study indicated that there are significant differences between different levels of water temperature 22 ^°C — 25 ^°C , 26 —31 ^°C and 34 — 37 ^°C for number of fry per female and number of fry per (gm) of female body weight of Oreochromis niloticus Also, the results indicated that there were a significant difference in rearing of fry at different stocking rates 300 fry / m³, 150 fry / m³ and 75 fry / m³, for growth parameters. The survival rate showed no significant differences between stocking rates 300 fry / m³ and 150 fry / m³, while, there was a significant different between them and stocking density 75 fry / m³. It was concluded that the water temperature 26 — 31^°C is the best for reproductive performance and growth. Also, stocking density 75 fry / m³ was the best result for growth of Nile tilapia than nthpr stnrkina densirv.