As malnutrition is a common complication among patients with cancer, it seems necessary identifying it with simple tools. Subjective Global Assessment (SGA) is useful to evaluate nutritional status on a basis of clinical parameters and can be used by any clinician with a basic training. Our intention is to determine usefulness of SGA applied by staff not working at Clinical Nutrition to guess if they identify properly malnourished patients. We included in our study thirty male and female patients with several types of active neoplasm who were being treated with chemo or radiotherapy. Oncology and Clinical Nutrition staff used SGA separately after the patients answered the form; there were also taken biochemical and anthropometrical determinations. Sixty-three percent of patient were diagnosed as malnourished or suspected being so by Oncologists, 30% by Clinical Nutrition staff and 26% by anthropometrical means. Incidence of malnutrition was low because the most common neoplasm among patients in the study was colorectal cancer. Oncologists tended to diagnose more cases of malnutrition due to a deficient training; nevertheless, SGA was useful because none of the malnourished patients was misdiagnosed and half of the well nourished patients were correctly identified as ones with no need for nutritional support.