Background: SAM children have increased requirements for phosphorus during recovery. If requirements are not met, they may develop refeeding hypophosphatemia leading to increased morbidity and mortality. However, no much studies known about the effect of current therapeutic diets (F-75 and F-100) on serum phosphate in SAM children.Methods: Prospective observational study, in which measuring serum phosphate at admission, at end of stabilization phase and at discharge in SAM children between 6-59 months.Results: Among 35 children enrolled, mean serum phosphate was 4.3 ±0.6 mg/dl at admission, 4.1± 0.8mg/dl at end of stabilization phase and 4.4±0.7mg/dl at discharge. 17% of children had hypophosphatemia at admission, 31% at end of stabilization phase and 17% at discharge. mean weight gain in hypophosphatemia and normophosphatemia groups are 1.3±1.46mg/kg/day and 2.51±2.63mg/kg/day (p=0.1) respectively. Mean duration of stay in hypophosphatemia and normophosphatemia groups are 11.6±1.26 and 10.26±1.54 days respectively (p=0.016).Conclusions: Hypophosphatemia was common among children with SAM at admission and increased at end of stabilization phase. Serum phosphate remains subnormal in about 1/5th of the children at discharge. This could be problematic for further recovery as phosphorus is needed for catch-up growth and bioavailability of phosphorus is low in local diets. Hence, authors suggest phosphorus supplementation in SAM children.