Laboratory experiments were conducted in Economic Entomology Department, Faculty of Agriculture, MansouraUniversity to estimate the heat requirements for Aphis nerii Boyer de Fonscolombe. attacking oleander shrubs at Mansoura district and its  predator Cydonia vicina isis Muls. The results assured that, the lower development threshold for the nymphal stage was 13.11 ºC , and the thermal units expressed as degree-days (dd's) required for nymphal stage were 98.53, 95.12 and 102.74 (dd's) at  20ºC, 25ºC and 28ºC, respectively and  the adult stages needed about 129.92, 140.66 and 153.27 day-degrees to complete their development on the three tested degree temperatures, respectively. The results indicated that the lower development threshold of the adults s were 12⁰C, 14⁰C for male and female, respectively and the degree day's at 20⁰C, 25⁰C and 28⁰C, were 538.4, 721.6 and 609.6 for male and 467.4, 610.5, and 565.6 for female.