Nutritional status can change during hospitalization. To evaluate the degree of change, a nutrition screening program (NSP) that included admission and 3-week reassessment was implemented. NSP parameters were weight for height, percentage of weight loss, arm muscle circumference, triceps skinfold, serum albumin, and total lymphocyte count. Nutritional risk factors (NRF) were also recorded: cancer, nothing by mouth (NPO) for 3 or more days, loss of appetite, difficulty chewing or swallowing, persistent fever, and cancer chemotherapy or radiation therapy. Of 15,876 patients admitted during the period of March 1982 through December 1982, 583 (3.67%) were found to be suffering from malnutrition or to have NRFs. Of the 583 patients, 182 received nutritional support and were excluded from the study. The remaining patients were reassessed after 3 weeks and had significant decreases in nutritional parameters; 622 patients with deficits in one parameter (visceral or somatic) on admission had a significant decrease in all parameters (p less than .001) on 3-week assessment. There was a deterioration in nutritional status in those patients entering the hospital with NRFs only or with one low parameter.