Type of feeding during early life influences growth trajectory and metabolic risk at later stage of life. Modifications in infant formulas composition have led to evaluation of their effects on growth and energetic efficiency (EE) compared to breastfeeding. Aim: To analyse type of feeding potential effects during first months of life, plus its EE, on growth patterns in healthy formula fed [standard (SF) vs. enriched (EF)] and breastfed infants (BF) participating in the COGNIS RCT up to 18 months of age. Methods: Infants follow-up to 18 months of age (n=141) fed with a SF (n=48), a bioactive nutrients-enriched infant formula (EF, n=56), or BF (n=37), were assessed for growth parameters using WHO standards. Growth velocity and catch-up were calculated to identify growth patterns. EE of breast milk/infant formula was also estimated. Results: Infants’ growth at 6 months showed higher length and lower HC gains in SF and EF infants than BF infants. Both Weight-for-length and Weight-for-age catch-up growth, showed significant differences in formula fed groups compared to BF. No significant differences in growth velocity or catch-up were found at 6-12 and 12-18 months. Regarding EE, infant formula groups showed significantly lower weight and length gains/gram of milk-protein, and higher weight and length gains/gram of milk-lipids, than BF infants. Conclusion: Growth velocity during first 6 months, which may be influenced by feeding, seems to be the main predictor of subsequent growth trajectory. Breastfeeding may have positive effects on growth programming due to the EE of its nutrients.