The aim of this work was to determine lipoprotein metabolism alterations in macrosomic newborns and to see whether these lipoprotein abnormalities are parallel or not to those found in their obese or nonobese mothers. Serum lipids, apo A-I, apo B100, lipoproteins (VLDL, LDL, HDL2, and HDL3), and LCAT activity were investigated in obese and nonobese mothers and cord blood of their macrosomic or appropriate-for-gestational-age (AGA) newborns. Serum and VLDL triglyceride concentrations were higher in obese mothers of AGA newborns than in nonobese mothers. Serum triglyceride, VLDL, and apo B100 levels were higher, while serum apo A-I and HDL2 cholesterol concentrations were lower in obese mothers of macrosomic newborns than in the other groups. In their macrosomic newborns, serum lipid, lipoprotein, apo B100, and apo A-I levels were higher as compared with those of other newborns. Macrosomic newborns of nonobese mothers had lipoprotein profiles similar to those in AGA newborns. LCAT activity was similar in both mother groups and in both newborn groups. In conclusion, maternal obesity and fetal macrosomia were associated with lipoprotein abnormalities consistent with high atherogenic risk.