The present study was designed to investigate the effects of magnetic water and different stocking densities on water quality parameters, growth performance, feed utilization, chemical composition and Blood biochemical of Nile tilapia (Oreochromis niloticus). A total of 180 healthy monosex Nile tilapia fingerlings with an average initial body weight of 33.24 ± 0.47 g were randomly distributed into 18 glass aquaria. The experiment was based on a 2 × 3 factorial design with three stocking densities; (5, 100, and 150 fingerlings/m³), and two types of water, normal water (NW) and magnetic water (MW). Experimental fish were fed on the commercial diet (30.11% protein) based on a feeding rate of 3% from body weight for all groups. Water quality parameters, growth performance parameters, feed utilization, chemical composition and blood parameters were calculated in all groups at the end of the experiment after eight weeks. The results indicated that water quality, growth performance, feed utilization, and chemical composition improved significantly in magnetic water groups compared to normal water groups at the three stocking densities. As for blood parameters, there were no significant differences in all groups. In conclusion, applying magnetic water on aquaculture of Nile tilapia farming improves water quality parameters, fish growth performance, feed utilization, and chemical composition at different stocking densities.