Introduction: Low Birth Weight (LBW), less than 2500grams, has significant effect on baby survival and growth. A good supportive care in addition to breastfeeding is very important. Breast milk fortification role is under research. Aims; To study the Efficacy of Human Milk Fortification in Low-Birth-Weight Infants Materials and Methods: This RCT was conducted at Department of pediatrics Lady Reading Hospital, Peshawar, Pakistan, from October 2021 to March 2022. A total of 60 low birth weight neonates were randomly allocated into two arms (group A fortified) and (group B unfortified) through non probability consecutive sampling technique. One group was given fortified expressed breast milk with 1g sachet of Human Milk Fortifier (HMF). The second group was fed with unfortified breast milk only. Babies were monitored every two-weekly with Biochemical markers. Data was analyzed through descriptive and inferential means using independent T Test. Results: The mean weight of neonates in the supplemented group was 2273.83g (Mean SD = 2273.83g 182.83g) and in the control group it was 2176.67g (Mean SD = 2176.67g 181.86g). Result shows that infants given human milk fortifier gain more weight as compared to breast milk. Statistical analysis also showed significant difference (P value 0.017) Conclusion: It is concluded that use of human fortified milk is helpful in gaining weight in low birth weight infants. It also improves serum calcium and protein levels.