This report explores and interprets statistical associations ofPleuronectes americanusegg contaminants with reproductive success. Winter flounder, a candidate for aquaculture, is at historically low abundance levels and has high prevalences of liver tumors. Pesticide and PCB concentrations of flounder eggs generally exceed those of more commonly analyzed marine samples, some being higher, others lower than egg concentrations linked to diminished reproduction of other resource species. Associations of individual contaminants of all chemical groups were mostly consistent with their uptake, metabolism, cumulation, toxicity, and egg concentration. Pesticides (20% of the mean total organic contaminant load of 3.2 μg/g dry weight) most strongly and significantly associated with increased mortality and defect of flounder embryos, followed by PAHs (10% of the organic contaminant load) and then metals. Total PCBs (70% of the egg organic contaminant load) had the weakest association with increased embryo mortality and defect, mostly accounted for by large concentrations of congeners with high potential toxicity. Other PCBs of low and high chlorine number and little or no known toxicity may act as toxin antagonists. Eggs of smaller flounder have increased concentrations of diverse contaminants. Eggs of older winter flounder have higher concentrations of cumulative compounds associated with detrimental reproductive effects.