Mortality factors and other life table data are presented forLaspeyresia pomonella(L.). Fecundity for the summer broods is ca. 50 eggs per female, with the spring brood females producing 25–30 each. Egg mortality ranges from 25% under caged conditions up to 50% under natural conditions. First-instar mortality is ca. 65%; and larval stages in apples suffer 35% mortality. The rate of mortality to 5th instars depends on the predators and parasites present, but a conservative estimate of 5th-instar mortality is ca. 30% in an unsprayed orchard. Pupal mortality is insignificant. Mortality to the overwintering larvae ranges from 50–75%, depending on what predators and parasites are present. These data should provide information necessary to develop an accurate simulation model of codling moth population dynamics.