Introduction:Choice of appropriate nutrition has a special place, which variations in dietary nutrient can potentially be involved in growth deficits in preterm neonates.Aim:to investigate the effect of protein supplementation in very low birth weight (VLBW= birth weight under 1500 grams) infants on neurological growth in the third year of birth.Material and Methods:We investigated neurological growth in two groups of control and intervention (each group, n= 18 subjects). The intervention group includes 3-year-old children who weighting less than 1200 grams at birth and have received protein supplementation at the course of NICU hospitalization, protein was added to maternal milk when the amount of milk reaches to 100 cc/kg/day, at this time parenteral nutrition was discontinued and the volume of feeding was increased 20cc/kg/day until reached to 150-180cc/kg/day. We also added the fortifier to breast milk at this time (FMS- Aptamil- DANON). The fortification and the protein supplementation were stopped when the weight of the baby reached to 1500 grams. The control group was fed similar to the intervention group, without protein supplemental intake. Neurodevelopmental outcomes were evaluated using ASQ, NEWSHA and BINS tools.Results:There was no significant difference between the mean head circumference in the two groups (p=0.209). There was no significant relationship between neurological growth rate evaluated by BINS tool in two groups (p=0.266). There was a significant correlation between the neurological development assessed by the ASQ tool in the areas of communication (p=0.014) and gross motor (p=0.001) in the two groups, however, no significant relationship was found in terms of fine motor (p=0.63), problem solving (p=0.07) and personal-social relationships in both groups (p=0.152). There was a significant correlation between neurological development evaluated using the NEWSHA tool in terms of auditory (p=0.031), verbal language (p=0.024), cognitive (p=0.007), social connection (p=0.034) and motor (p=0.002) in the two groups.Conclusion:Protein intake in preterm infants didn’t reveal long term effects on the growth of head circumference. Moreover, it was capable of improving neurological growth in the areas of communication and gross motor (based on the ASQ) and auditory, verbal language, cognitive, social connection, and motor (based on the NEWSHA).