Objective: To evaluate the effectiveness of F 75 and F 100 in children with severe acute malnutrition. Study Design: Cross Sectional study. Setting: National Institute of Child Health, Karachi. Period: 1st Jan 2021 to 30th June 2021. Material & Methods: All children with severe acute malnutrition, aged 6 months to 5 years, irrespective of gender were included in the study. Children of parents/guardians who failed to give consent were excluded from the study. Relevant history was recorded. After acute intervention as per departmental standards, F-75 was initiated. When the subject gained weight at the rate of 0.5g per kg/day for three consecutive days, the patient was then administered F-100. Both diets were administered 6-8 times a day. Outcome was recorded by comparing the post treatment mean weight with baseline weight. Results: The mean age of the child and the mother were 30.53 ± 13.37 months and 31.31 ± 6.34 years, respectively. The mean increase in weight was 0.75 ± 0.77 kgs (Pre- and post-treatment). Increase in BMI was 1.12 ± 1.34 kg/m2 while the increase in MUAC was 0.93 ± 0.89 cm. Statistically significant increments were observed in weight, MUAC, and body mass index after administration of F75/F100 diet in the severely malnourished children (p<0.0001). Conclusion: The present study revealed statistically significant increments in weight, MUAC, and body mass index, after administration of F75/F100 diet in the severely malnourished children.