The scored Patient-Generated Subjective Global Assessment tool (PG-SGA), regarded as the most appropriate means of identifying malnutrition in cancer patients, is often challenging to implement in a busy outpatient setting. We assessed the validity of an abridged version of the PG-SGA (abPG-SGA), which forgoes the physical examination, and compared its usefulness in discerning malnutrition to the full PG-SGA and Malnutrition Screening Tool (MST). The nutritional status of 90 oncology outpatients receiving chemotherapy was assessed according to SGA global rating, PG-SGA, and MST. Receiver operating characteristic (ROC) curves were generated to estimate the sensitivity and specificity of various cut-off scores for malnutrition. Thirty-six percent of patients were malnourished (SGA). The abPG-SGA yielded 94% sensitivity and 78% specificity and area under the curve (AUC) = 0.956, which was slightly lower than PG-SGA (97% sensitivity, 86% specificity, AUC = 0.967) and higher than MST (81% sensitivity, 72% specificity, AUC = 0.823). Patient reported symptoms included loss of appetite (30%), altered taste (31%), fatigue (30%), and decreased ability to perform activities of daily living (53%). In conclusion, the abPG-SGA is a practical, informative and valid tool for detecting malnutrition in the outpatient oncology setting.