OBJECTIVE Lactating women in New Mexico have low levels of important fatty acids relative to reported international data. The objective was to correlate the proportions of long-chain polyunsaturated fatty acids (LCPUFA) in the serum phospholipids in mothers and newborns within the same population. METHODS The serum phospholipids of 52 maternal:neonatal pairs were analyzed. Maternal samples from consecutive admissions were collected at hospital admission, and umbilical cord blood samples were collected at delivery. Fatty acid methyl esters were prepared and then separated and quantified by gas-liquid chromatography. RESULTS The median maternal percentages of arachidonic acid (AA) (4.9%), eicosapentaenoic acid (EPA) (0.27%) and docosahexaenoic acid (DHA) (2.07%) were below reported international levels. The percentages of AA (9.6%) and DHA (3.2%) in cord serum phospholipids were much higher than maternal samples but remained lower than reported internationally, whereas cord EPA (1.1%) was higher than reported. The highest percentage of DHA in serum phospholipids was found in the Asian subjects (4.21 ± 0.41%), while the American Indian women had the lowest DHA percentage (1.38 ± 0.26%). The maternal DHA percentage was negatively correlated with parity (r = -0.22, p = 0.04). CONCLUSIONS In the setting of low maternal levels of important fatty acids, their newborns did not accrue serum levels equivalent to reported international values.