Technical Abstract: The cotton aphid, Aphis gossypii (L.) (CA) and green peach aphid, Myzus persicae (Sulzer) (GPA), are polyphagus sap feeders and major crop pests. CA has become an important cotton pest, causing mid-season damage and now late season concerns over lint contamination with honeydew (called sticky cotton). GPA vectors plant disease such as Virus Yellows that may cause 30% losses in beets. This study characterized nine host plants for age-specific fecundity and survival. Individuals were held on detached leaves in petri dishes in an incubator under controlled light, temperature, and humidity. Jackknife resampling was used to statistically test for differences among demographic variables. The cotton aphid had greatest intrinsic rate of increase on bean, kenaf, and shepherd’s purse. The green peach aphid had greatest intrinsic rate of increase on shepherd’s purse, fiddleneck, pepper, and malva. Pepper was a poor host for cotton aphid, while cotton was a poor host for green peach aphid, and Powell’s amaranth was a poor host for both aphid species. Variations in the ranking patterns of host plants among fecundity, survival, and intrinsic rate of increase are discussed. Phylogenetic relationships among plants did not show a consistent pattern with aphid suitability. Previous studies indicate how the results may be used to predict population growth at other temperatures, which will be useful for field predictions of aphid populations. The information may be used to manage the seasonal migration of aphids from weedy overwintering hosts to crops.