Mortality to the egg stage of Colorado potato beetle,Leptinotarsa decemlineata(Say), from endemic predators was assessed in unsprayed plots within commercial potato fields in western Massacusetts in 1986 and 1987. Direct measurement of recruitment into the egg stage and of losses to predation gave estimates of total stage-specific mortality for each generation of Colorado potato beetle and daily mortality rates. Abundance of endemic egg predators was measured through direct observation and trapping.Coleomegilla maculata(DeGeer), a coccinellid, was the most abundant predator and the only one consistently present whenever Colorado potato beetle eggs were in the field. Total mortality to eggs from predation was 39.9% in the second generation of 1986 and 37.8% and 58.1% in the first and second generations of 1987, respectively. Daily mortality rate did not change significantly during large fluctuations in prey density. Results suggest thatC. maculatacan contribute to the control of both early and late generations of Colorado potato beetle and efforts to conserve this natural enemy will help reduce the need for chemical control.