Climate change could profoundly affect the status of agricultural insect pests. This study predicts expected peach fruit fly (PFF) annual generations under current and future climate by using the accumulated thermal heat units expressed as degree-days unit (DDU). We evaluated how temperature expected to influence the annual generation numbers in three governorates of Egypt using the climate change data output from the HadCM3 model for A1 scenarios proposed by the Intergovernmental Panel on Climate Change. Results indicated that PFF in Asyout have the highest number of possible generations as compared to other locations (North Sinai and EL Beheira) under current climate to be 8 compared with 6 and 7 for other locations, respectively. Generation numbers of PFF under climate change conditions would be increased especially in Asyout governorate to 9 and 10 by 2050 and 2100, respectively. However, the expected generation numbers of PFF at 2050 and 2100 will be 8-9 and 9-10 generations per year for other two locations, respectively.