The effect of different prey densities and prey stages of Tetranychus urticae on feeding capacity and fecundity of Phytoseiulus persimilis adult females was studied on leaf discs of eggplant, Solanum melongena L. (Black Baladi cultivar) during ten days under laboratory consistent conditions of 25 ± 2°C and 65 ± 2% R.H.. The following prey densities were tested: 5, 10, 15 and 20 for the tested stages of prey (eggs, larvae, males and females). It was found that all of the prey tested stages were eaten by P. persimilis females. The total average of devoured prey individuals per predator female during ten days was significantly (P ≤ 0.05) affected by stage and density of the introduced prey. In all cases, number of preys consumed by predator was increased with increasing prey density. P. persimilis consumed more eggs and larvae than males and females of the prey. Total averages of consumed T. urticae eggs and larvae were 35.5, 23.7; 67, 40.1; 82.2, 54.0 and 118.8, 77.2 at prey densities of 5, 10, 15 and 20, respectively. The highest consumption was detected when thepredator fed on T. urticae stages at a density of 20/prey. Eggs laid by predator female were differed significantly (P ≤ 0.05) according to stage and density of the introduced preys during the experimental period. The greatest number of deposited eggs was observed when feeding on T. urticae eggs followed by females at different prey densities. Total averages of P. persimilis eggs were 10.7, 19.4, 29.7 and 32.7 eggs (for prey eggs) as well as 9.2, 13.4, 22.5 and 25.9 eggs (for prey females), at prey densities of 5, 10, 15 and 20, respectively. Differences in total number of deposited eggs of P. persimilis were not significant (P ≤ 0.05) when the predator was provided with larvae, males and females at each of the tested densities of T. urticae. A positive and high significant correlation was found between densities of prey stages and each of feeding capacity and fecundity of the predator. Daily number of deposited eggs was gradually increased to reach the highest value on the sixth day in most cases. Thereafter, the deposited eggs were decreased to the end of experiment. The present study suggests the possibility of utilization P. persimilis as an ideal biocontrol agent to reduce T. urticae populations on eggplants.