The daily dietary camitine (C) intake for the breast-fed (BF) neonate is 2-5 mg/Kg. Cow milk contains nearly twice the concentration of human milk (HM)(60-70 nmol/ml); when this is used to prepare formula (F) the C concentration is approximately the same as that of HM. Dietary C appears to be a major factor in the accretion of C in neonates. Plasma-free C (FC) <20 nmol/ml shows “C-deficiency” and a FC/TC (free camitine/total camitine) ratio <0.7 is considered a marker of “C-deficiency”. SC+LC/FC ratio (short+long acylcamitines/free camitine) >0.4 indicates“C-insufficiency”. Plasma C levels and its esters were analyzed for BF term infants and neonates fed with one of two formulas (120-125 Kcal/Kg/day); either standard F or C-supplemented (2.2 mg/d) formula (SF).METHODS: 66 full term newborn infants were subdivided into three groups; BF; 22, F:22 and SF:22. All of them were homogeneous for gestational age, birth weight and ponderal index. The samples were obtained in the early(ENP) and late (LNP) neonatal periods (weight increase 29.8-32.2 g/day), measuring plasma FC, TC, SC and LC (nmol/ml) (modified radioisotopic method-McGARRY, 1976). ANOVA, Student “t” test for paired data*=p<0.05. RESULTS: At LNP, FC and TC were higher than at ENP in the three groups, and no statistical differences were found. In F fed infants SC decreases at LNP compared with ENP (4.3±0.97 vs 10.61±17* and is lower than the levels found at LNP of BF(8.12±2.20) and SF (9.82±2.59) fed neonates. Moreover, at LNP, F fed infants have higher plasma levels of LC (7.80±0.34) than ENP(5.90±0.26*). In all groups the FC/TC ratio was higher at LNP than at ENP; on the contrary the SC+LC/FC ratio decreases at the LNP compared to the ENP. None of the neonates studied have FC<20 nmol/ml. The 3p value for FC/TC in BF is 0.54 and 97p for SC+LC/FC ratio is 0.83. DISCUSSION AND CONCLUSION: There is a significant accretion of C by muscle and liver tissues during the last trumester of gestation, and a continuous postnatal increase. Our results agree with other authors. Plasma C concentration of BF, F and SF-fed term neonates increase approximately 2-fold during the first month of life. The index ranges for “C-deficiency” or“C-insufficiency” must be reviewed for neonates. SF fed infants have similar plasma C and acylcamitine concentrations to those of BF infants.