The biological aspects of the predatory mite, Agistemus exsertus Gonzalez (Acarina : Stigmaeidae) were studied at different types of food (the two spotted-spider mite, Tetranychus urticae Koch eggs, and immature stages, the purple scale,Lepidosaphes beckii (Newm.) eggs and pollen grains of the date palm). Generally, the biological aspects of the predatory mite were affected by food types. The incubation period of A. exsertus was (3.95±0.54, 4.75±0.17, 4.57±0.47 and 4.42±0.30 days at 28°C, when fed on eggs, immature stages of T. urticae, eggs of L. beckii and pollen grains of date palm, respectively. Similar results obtained for larval, protonymphal and deutonymphal stages. Female and male longevities were long with feeding onpollens, while, it was short with feeding on T. urticae eggs at 28°C. It could be concluded that T. urticae eggs or immature stages were more favourable diets for female and male under constant temperature. Also, female and male life span of A. exsertus affected by kind of food, the longest period was recorded when fed on date palm pollens. The pre-oviposition, oviposition and post- oviposition periods for female were affected by types of food. The total numbers of deposited eggs/female of A. exsertus was affected by the types of food offered to adult female. The number of deposited eggs/female increased with supporting the suitable prey for adult female. Sex ratio was affected by kind of food. The highest percentage of female's percentages of A. exsertus  was (66.24%) recorded when fed on T. urticae eggs, while the lowest one was recorded (61.05%) when fed on fed on pollens.  Feeding capacity of A. exsertuswas affected by predator stage sex. The average number and daily rate of consumed prey increase with the successive predator developmental stages. Also, the immature of female fed on greater number of prey than of those of male. Male followed similar trend as that of female, but in smaller numbers. Concerning the feeding capacity of adult's it is clear that the female consumed higher numbers of prey than male, these due to those females eggs production.