Background:  Refeeding syndrome (RFS) is a life-threatening, underdiagnosed, and under-researched complication in treating children with severe acute malnutrition (SAM). This study aimed to determine the incidence and onset of RFS and identify biochemical abnormalities, clinical signs, and complications associated with RFS development in children 0–59 months treated in a South African public hospital setting. Methods:  A retrospective cohort study was performed on hospital files of children diagnosed with SAM at Rahima Moosa Mother and Child Hospital, Johannesburg, from 1/10/2014 to 31/12/2018. A total of 148 files could be retrieved from the hospital archives. The diagnosis of SAM based on the World Health Organization definition was confirmed in 126 of these children, and they were included in the study. The onset of RFS among the included children was diagnosed according to published guidelines based on the onset of hypophosphatemia. Children who developed RFS and those who did not were compared concerning biochemistry and clinical signs and symptoms on admission. Results:  The median age of the 126 children (63% male) with confirmed SAM was 34 months (IQR: 26.0 to 48.4 months)). The mortality rate was 18.2%. Of these children, 8.7% were retrospectively diagnosed as having developed RFS during their recorded hospital stay, despite implementing the WHO treatment guidelines for SAM. A significantly higher percentage of the children that developed RFS presented on admission with hypophosphatemia (p=0.04), severe hypokalemia (p=0.0005), hyponatremia (p=0.004), an international normalized ratio (INR) of above 1.7 (p=0.049), diarrhea (p=0.04), dehydration (p=0.02) and urinary tract infection (UTI) (p=0.04) than those that did not. Edema was more prevalent on admission in children who developed RFS than those who did not (63.6% vs 39.1%), though the difference was not statistically significant. Children who developed RFS stayed in hospital significantly longer than those who did not (18 vs 12 days) (p=0.003). Conclusion:  In this population of children with SAM treated in a South African public hospital, the presence on hospital admission of low levels of electrolytes, elevated INR, dehydration, diarrhea, and UTI was significantly associated with developing RFS. Recognizing these as possible red flags for developing RFS in children admitted with SAM might contribute to improved outcomes and needs further investigation.