To explore the effect of maternal dietary intervention on infant essential fatty acid (FA) status, we conducted a prospective, single-blind, randomized nutrition intervention study. At the first trimester of pregnancy, 90 women from families with a history of allergy were randomized either to receive intensive dietary counseling to modify dietary intake according to current recommendations or as controls. Infants' cord and 1-mo isolated serum phospholipid FA were identified and quantified by GC. Detectable levels of eicosatrienoic acid [ETA, 20:3(n-9)] were taken as a biochemical marker for essential FA deficiency, and the DHA sufficiency index [22:6(n-3):22:5(n-6)] and the DHA deficiency index [22:5(n-6):22:4(n-6)] were taken as markers for DHA [22:6(n-3)] status. The concentration of ETA was lower in cord blood in the intervention (I) group [median 0.64 (IQR 0.40-0.78) mg/L; 2.09(1.31-2.54) mu mol/L] than in the control (C) group [0.92 (0.54-1.20) mg/L; 3.00(1.76-3.92) mu mol/L] (P = 0.048). The proportion of ETA in total FA in the I group [0.73% (0.48-0.85%)] was lower than in the C group [0.93% (0.78-1.22%)] (P = 0.003). A higher DHA sufficiency index and lower DHA deficiency index were detected in cord blood in the I group than in the C group, although the groups did not differ in the DHA concentration or proportion of the total FA. There were no differences among groups at 1 mo for any of the variables measured. Our findings suggest a better supply of essential FA, particularly important during the period of rapid development, in infants whose mothers received dietary counseling. The results thus highlight the importance of maternal diet for child health, calling for dietary counseling for pregnant women in primary health care. J. Nutr. 141: 1281-1285, 2011.