This research was conducted to determine the effects of pre-incubation warming on the hatchability of post-peak egg production broiler breeder eggs. An experiment with six trials was conducted with 7,920 freshly laid eggs from Ross 308 and 708 broiler breeders from 61-67-wks of age. For each trial, 1,320 eggs were used to determine if pre-incubation warming treatments of 0, 2, 4, and 6, or 0, 3, 6, and 9, or 0, 9, 12 and 15 hrs (at 37.6°C) could improve the hatchability of eggs stored (at 15.5°C) for three days. After a storage period of three days, the eggs were incubated for 21d. Unhatched eggs were broken to determine fertility, and if fertile, stage of embryonic death. Time of hatch was observed for pre-incubation warming treatments 0, 9, 12, and 15 hrs. Of the chicks that hatched, two trials were conducted, each using 192 randomly selected males to determine if the pre-incubation warming treatments affected initial weight, final weight, average daily gain, or feed conversion ratio. Statistical significance was assessed at P < 0.05. Pre-incubation warming of 6 hrs or less did not significantly affect fertile hatchability, total hatchability, embryonic morality or pips. However, pre-incubation warming of 15 hrs negatively affected early-dead mortality (11.6%) when compared to eggs that did not receive any pre-incubation warming (8.7%). Pips were significantly reduced in eggs that were treated for 9, 12 and 15 hrs (1.4, 1.3, and 0.3%, respectively) when compared to eggs that did not receive pre-incubation warming (2.4%). Average hatch time was shortened by pre-incubation warming of 9, 12, and 15 hrs with differences of 5, 7, and 12 hrs, respectively, compared to the eggs that were not pre-incubated. Average final weight, average daily gain, and feed conversion ratio were not significantly different at the end of an 18d trial period. The results of this study provide evidence that pre-incubation warming within a range of 2-15 hrs does not improve hatchability of post-peak broiler breeder eggs when stored for three days. The most significant finding is that eggs can be pre-warmed at incubation temperature for 15 hrs without negatively affecting hatchability.