BACKGROUND: Pregnant women and children are especially vulnerable to exposures to food contaminants, and a balanced diet during these periods is critical for optimal nutritional status. OBJECTIVES: Our objective was to study the association between diet and measured blood and urinary levels of environmental contaminants in mother-child pairs from six European birth cohorts (n = 818 mothers and 1,288 children). RESULTS: Maternal high (>= 4 times/week) versus low (<2 times/week) fish consumption was associated with 15% higher PCBs [geometric mean (GM) ratio= 1.15; 95% confidence interval (CI): 1.02, 1.29], 42% higher perfluoroundecanoate (PFUnDA) (GM ratio = 1.42; 95% CI: 1.20, 1.68), 89% higher mercury (Hg) (GM ratio =1.89; 95% CI: 1.47, 2.41) and a 487% increase in arsenic (As) (GM ratio = 4.87; 95% CI: 2.57, 9.23) levels. In children, high (>= 3 times/week) versus low (<1.5 times/week) fish consumption was associated with 23% higher perfluorononanoate (PFNA) (GM ratio = 1.23; 95% CI: 1.08, 1.40), 36% higher PFUnDA (GM ratio= 1.36; 95% CI: 1.12, 1.64), 37% higher perfluorooctane sulfonate (PFOS) (GM ratio =1.37; 95% CI: 1.22, 1.54), and >200% higher Hg and As [GM ratio =3.87 (95% CI: 1.91, 4.31) and GM ratio= 2.68 (95% CI: 2.23, 3.21)] concentrations. Using TMLE analysis, we estimated that fish consumption within the recommended 2-3 times/week resulted in lower PFAS, Hg, and As compared with higher consumption. Fruit consumption was positively associated with OP metabolites. Organic food consumption was negatively associated with OP metabolites. DISCUSSION: Fish consumption is related to higher PFAS, Hg. and As exposures. In addition, fruit consumption is a source of exposure to OPs.