This study was prospectively conducted to investigate any relationship of nutritional status at the time of admission to length of hospital stay and mortality. All patients admitted to the Asan Medical Center between October 13 and November 12, 1997 who met the study criteria were included in the study. Patients were classified as Not-at-risk, At-risk Ⅰ or At-risk Ⅱ based on the levels of serum albumin and total lymphocyte count in a computerized nutrition screening program. Sixty three percent of the patients were classified as Not-at-risk Group, 29% as At-risk Group Ⅰ and 8% as At-risk Group Ⅱ. Significant correlation was observed between nutritional status and LOS (P＜0.01) as well as mortality rate (P＜0.05). The more the patient had the nutritional risk factors, the longer the LOS and the higher the mortality rate were. Further studies have to be done in order to demonstrate cost-effectiveness of medical therapy for the malnourished hospitalized patients.