The Mini Nutritional Assessment (MNA) is a clinical tool designed for assessing nutritional status of elderly patients. Used in preoperative evaluation of ambulatory patients over 60 years of age seen on anesthesia consultation in a previous study, it identified 6.9% patients with overt malnutrition out of a group of 408. However, four-fifths of 291 ASA 1-2 patients were well nourished, and underwent needless, non-contributory and time-consuming test. The MNA-Short Form (MNA-SF) has recently been devised as the first step of a two-step process: if negative, there would be no need to complete "full" MNA. Therefore, the base data of 408 MNA forms completed during the above-mentioned study was used for the purpose of comparing the MNA-SF to the MNA, to test whether the MNA-SF could have been the first step of a two-step nutritional evaluation of anesthesia patients. Median (range) age, and BMI were 72 (60-98) years, and 25.2 (12.8-40.4) kg x m(-2), respectively. There were equal numbers of men and women. In 144 cases, the MNA-SF was found positive (35.3%) with a median MNA of 21.5 (1.5-27) points. The MNA-SF predicted absence of overt malnutrition revealed by the MNA, with 100% sensitivity and negative predictive value (NPV). It was found less efficient for predicting absence of "possible" nutritional problems detected by the MNA (sensitivity 85.6% and NPV 92.8%). However, none of the 19 borderline patients would have had overt malnutrition, being only found "at risk of malnutrition" by the MNA. On the studied sample, the MNA-SF would have correctly sorted out 69.5% of the patients without severe malnutrition. We believe the MNA-SF should be used as the first step of an efficient preoperative nutritional evaluation of ambulatory elderly patients.