This study was performed to investigate the effect of changes at lightining program of broiler breeder in prelaying period on body temperature and oxidative stress parameters. The study was carried out to on four different broiler breeder including Ross-308 pens (2 Test and 2 Control) of a commercial company. Test groups of the study were exposed to yellow light 4 times during half an hour at interval for 3 days from the weeks of 22^nd. At the end of the fourth application, 15 female and 15 male chickens were chosen from each group. Their body temperature were measured by digital thermometer and blood samples were taken. The changes applied at ligtining program increased the body temperature (P<0.01) and molondialdehid level (P<0.05) in the blood samples of the chickens. There was no signicant difference between groups in superoxit dismutase, glutation peroxidase, catalase enzyme activities and glutation level. In conclusion, it was found that applied random arrangements at lightining program in prelaying period affected physilogically and caused stress in of broiler breeders.