Background: Beginning in December 2019, the 2019 novel coronavirus disease (COVID-19) has caused a pneumonia epidemic that began in Wuhan, China, and is rapidly spreading throughout the whole world. Nutrition support has become one of the important treatments for severe and critical patients. Objective: To assess the adequacy of nutritional support in COVID-19 patients receiving oxygen support. Methods: A multicenter prospective study enrolled 88 COVID-19 patients receiving oxygen support in Fedail Hospital, Albaraha Hospital, Aliaa Hospital, and Royal Care Hospital during the period from January to April 2021. Data regarding demographics, comorbidities, types of oxygen therapy, vital signs, laboratory investigations, methods of nutrition support, estimated calorie achievement, and outcomes were collected. Nutritional adequacy was assessed by using the Nutritional Risk Screening-2002 (NRS- 2002) test. Results: Among 88 patients, 50(56.8%) were males and 38(43.2%) were females; their mean age was 67±11 years. CPAP (n=28; 32%) and mechanical ventilation (n=27; 27%) were the main types of oxygen therapies. Estimated calories were achieved in only 36(40.9%) of patients and failure to the achievement of estimated calories was commonly due to hypoxia (n=33; 37.5%) and poor appetite (n=23; 26.1%). About 66(75%) patients were adequately nourished, 16(18.2%) were at risk of malnutrition, and 6(6.8%) patients were malnourished. The mortality was significantly associated with malnutrition (P. value= 0.000), and parental feeding modes (P. value= 0.000), and underweighted BMI (mean= 17.8 kg/m2; P. value= 0.000). Moreover, multi-organ failure was significantly correlated with risk of malnutrition (P.value= 0.000), NG feeding (P. value= 0.000) and overweighed BMI (mean= 28.8 kg/m2; P. value= 0.000). Additionally, mortality and multi-organ failure were significantly correlated with hypoalbuminemia among our study subjects (P. value= 0.001). Conclusion: The rates of malnutrition and risk of malnutrition were 6.8% and 18.2% among COVID-19 patients who received oxygen therapy, respectively. Inadequacy of nutritional support or failure in the achievement of estimated calories among our study subjects were commonly due to hypoxia and poor appetite. Mortality was significantly associated with malnutrition, parental feeding modes, and underweighted BMI. Furthermore, multi-organ failure was significantly correlated with the risk of malnutrition, NG feeding, and overweighed BMI. Both, mortality and multi-organ failure were correlated with hypoalbuminemia.