Objective. Evaluate the lipidie metabolism of gestating sows in response to a modification in the fat level of the diet and its effect on fetal nutrition through metabolic indicators. Materials and methods. Fifty-six first-timers or multiparous sows were selected receive a diet without adding extra fat (SAp or SAm) or with extra fat addition (AGp o AGm). The SA diet consisted in feeding a conventional commercial diet of 3 kg/day, in the AG diet the corn was reduced and soybean oil was included to supply 20% extra fat. Blood samples were collected at 85, 100, 113 days of gestation and 24 hours postpartum, and on 50% of the piglets born alive per litter. Serum cholesterol (CT), triglycerides (TG), high (HDL) and low (LDL) density lipoproteins, non-esterified fatty acids (NEFA) and beta hydroxybutyrate (BHB) were analyzed. Results. The Serum concentrations of HDL, LDL, CT NEFA, BHB, and TG (p<0.01) increased in sows on days 100 and 113, but decreased at 24 hours postpartum. Blood metabolites in piglets under the influence of both treatments showed significant differences (p<0.01). Conclusions. There was no statistical effect from the modification of dietary fat on LDL and NEFA; for the remaining indicators differences were evident in pregnant sows. There was no correlation between metabolic indicators in mothers and piglets. [ABSTRACT FROM AUTHOR]