Abstract: The effect of temperature on the development of the aphid parasitoid Diaeretiella rapae (M’Intosh) stages was evaluated on certain aphid species (Brevicoryne brassicae L., Aphis nerii Boyer, Aphis craccivora (Koch) and Hyalopterus pruni (Geoffroy). Laboratory studies were conducted to study the effect of different temperature degrees; (10, 15 and 25°C) on the developmental stages of the parasitoid Diaeretiella rapae, reared on certain aphid species (B. brassicae, A. nerii, A. craccivora and H. pruni). The results indicated that the duration of the parasitoid was longer at 10°C. As temperature increased from 10-25°C the longevity decreased, the lower thermal threshold for the development of D. rapae 1.99, 0.46, 1.49 and 5.56°C for eggs, 3.67, 9.1, 17.95 and 3.98°C for larvae, 7.36, 7.0, 3.2 and 3.09°C for pupa while it were 2.93, 5.14, 6.09 and 3.5°C for the total duration from (egg to adult). The heat units requirement for the development of eggs were 84.55, 102.57, 73.3 and 69.14 DD’s, for larvae were 86.41, 48.31, 36.74 and 104.19, for the pupal 56.93, 69.82, 74.92 and 116.69 DD’s and 241.08, 207.59, 149.07 and 286.53 DD’s on for the development period B. brassicae, A. nerii, A. craccivora and H. pruni, respectively. The lower thermal threshold for longevity (female and male) of D. rapae were 4.18 and 1.93, 3.13 and 1.31, 3.39 and 1.14 and 2.84 and 1.49°C and the heat units requirement for longevity of (female and male) were 81.76 and 70.26, 68.04 and 54.04, 71.83 and 64.03 and 62.71 and 51.23 on the same aphid species, respectively. Obtained results provide essential information for predicting the field population of the parasitoid D. rapae, releasing time on certain aphid species for controling these pests and it is recommended to be an item of Integrated Pest Management Programs in Egyptians fields designed to control certain aphid species.