Abstract Gastric bypass has grown in popularity in recent years due to its high efficacy in achieving long-term weight loss in patients with morbid obesity. Gastric bypass has been described to further exacerbate baseline nutritional deficiencies due to reduced gastric capacity and malabsorption. In rare cases, when protein deficiency is severe, Kwashiorkor disease may arise. The incidence of Kwashiorkor specifically following gastric bypass is rare, with an incidence of 4.7%. We report a case of a female patient who underwent a gastric bypass and subsequently developed Kwashiorkor. Physicians’ suspicion of index for Kwashiorkor should be high for patients presenting with signs or symptoms of severe malnutrition following weight-loss procedures.