The purpose of this study was to evaluate the effects of nutritional supplementation on nutritional status, ventilatory performance, and exercise tolerance for persons with chronic airflow limitation (CAL). The hypotheses were that long-term supplementation with a high fat, low carbohydrate formula would improve nutritional status, ventilatory performance, and exercise tolerance. Thirty-five elderly subjects with stable but irreversible airway limitations were recruited from the outpatient clinics of the Veterans Affairs Medical Center and randomly assigned to a control or supplement group. The 18 subjects in the supplement group ingested one can of Pulmocare (Ross Laboratories, Columbus, OH) per day for nine weeks while the 17 control subjects maintained normal dietary routines. Evaluations of outcome variables were performed every three weeks for nine weeks. Multivariate analyses of variances for repeated measures indicated that the supplemented group demonstrated a significantly greater weight gain (F$sb1□,33 □$= 5.76; p =.02), increase in skinfold thicknesses (F$sb1□,33 □$= 9.38; p =.004), and increase in percent body fat (F$sb1□,33 □$= 15.17; p =.005). No significant differences were found in ventilatory performance. The experimental group was able to increase a 6-minute walking distance by a mean of 117 feet, compared to a decrease of 5 feet by the control group. A univariate ANOVA indicated that this change was significant at six weeks (F$sb1□,32 □$= 5.03; p =.03). The ingestion of the supplement did not reduce normal caloric intake. This study demonstrated that dietary supplementation for undernourished persons is beneficial. For persons with CAL, improved nutritional status and greater walking distance may contribute to improved ability to perform activities of daily living.