We investigated whether maternal fat intake alters amniotic fluid and fetal intestine phospholipid n-6 and n-3 fatty acids. Female rats were fed 10% by weight diet from fat with 20% linoleic acid (LA, 18:2n-6) and 8% alpha linolenic acid (ALA, 18:3n-3), (control, n=8) or 72% LA and 0.2% ALA (n-3 deficient, n=7) from 2 week before then throughout gestation. Amniotic fluid and fetal intestine phospholipid fatty acids were analyzed on day 19 gestation using HPLC and GLC. Amniotic fluid had significantly lower DHA, and higher docosapentaenoic acid (DPA, 22:5n-6) in the n-3 deficient than control group (DHA 1.29±0.10 and 6.29±0.33; DPA 4.01±0.35 and 0.73±0.15 g/100g fatty acids, respectively); these differences in DHA and DPA were present in amniotic fluid cholesterol esters and phosphatidylcholine (PC). Fetal intestine in the n-3 deficient group had significantly higher LA, arachidonic acid (20:4n-6, ARA) and DPA and lower eicosapentaenoic acid (EPA, 20:5n-3) and DHA in PC, and significantly higher DPA and lower EPA and DHA in PE than in the control group; the n-6/n-3 fatty acid ratio was 4.9±0.2 and 32.2±2.1 in PC and 2.4±0.03 and 17.1±0.21 in PE in the n-3 deficient and control group intestine, respectively. We demonstrate that maternal dietary fat influences amniotic fluid and fetal intestinal membrane structural lipid essential fatty acids. Maternal dietary fat can influence tissue composition by manipulation of amniotic fluid which is swallowed by the fetus, or by transport across the placenta.