Serum lipids/lipoproteins were assayed to evaluate the diagnostic values of serum lipids/ lipoproteins in neonatal late onset sepsis (NLS) in 36 episodes of NLS (15 of the 36 in preterm newborns and 21 of the 36 in term newborns) while 36 healthy newborns were used as controls. On d 0, levels of total cholesterol (TC), triglyceride (TG), lipoprotein-a (Lp-a), high-density lipoprotein (HDL) and apolipoprotein-A (Apo-A) and B (Apo-B) were found to be significantly lower in the NLS group than in the control group (p=0.001). The sensitivity and specificity values were 61.5% and 69.4% for TC, 96.2% and 44.4% for HDL, 73% and 50% for Lp-a, 69.2% and 83.3% for triglyceride, 73% and 97.2% for Apo-A and 77% and 69.4% for Apo-B, respectively, at diagnosis. In conclusion, Apo-A appeared to be a useful marker for detection of NLS. Low TG levels may be due to impaired triglyceride-related neutralization of lipopolysaccharides in NLS.