Abstract.1The relationship between parasitization byEdovum puttleriGrissell and density of eggs of the Colorado potato beetle,Leptinotarsa decemlineataSay (Coleoptera: Chrysomelidae), was studied on two spatial scales (eggs mass and 6 m2cage).2For both scales, rates of parasitism were generally inversely related to host density for periods ranging from 2 to 8 days after parasitoid release. Thereafter, parasitism became independent of host density.3The initial inverse‐density relationship and subsequent shift to density independence may result from several factors: (1) ambient temperatures, (2) the parasitoid's limited egg production, (3) differential times of exposure of egg masses to parasitoids, and/or (4) the parasitoid's patterns of host feeding and oviposition.4Although overall levels of parasitism were relatively low, total mortality ofL.decemlineataeggs (including nonviable and cannibalized eggs, and those killed by parasitoid feeding) in parasitized egg masses was consistently high (˜70–