The Salmon in Pregnancy Study provided two meals of salmon per week to pregnant women from week 20 of gestation; the control group maintained their habitual diet low in oily fish. Salmon is a rich source of marine n-3 fatty acids. Since marine n-3 fatty acids may increase oxidative stress, we investigated whether increased salmon consumption could affect markers of oxidative stress in mid and late pregnancy. Urinary 8-iso-prostaglandin F(2α), urinary 8-hydroxy-2'-deoxyguanosine, and plasma lipid peroxide concentrations did not change from week 20 to 38 of pregnancy and were not altered by increased consumption of salmon. Thus, increased intake of salmon during pregnancy does not increase oxidative stress, as judged by the markers of oxidative damage to lipids and DNA measured herein.