To compare the results of different nutritional screening tools, including NRS-2002, PG-SGA, and NUTRISCORE for the detection of malnutrition in oncology outpatients. A descriptive study. Place and Duration of the Study: Daily Chemotherapy Unit, Umraniye Training and Research Hospital, Istanbul, Turkiye, between June and July 2021. A total of 69 patients were included in the study, receiving cancer therapy in an outpatient setting. The NRS-2002, PG-SGA, and NUTRISCORE scores were calculated to determine the nutritional status. The mean age of the patients was 56.74 ± 13.48 years, and 59.4% were females. The mean BMI was 27.29 ± 5.27 kg/m2. Among the patients, 55.1% had insufficient nutritional intake or were at risk of malnutrition according to the NRS-2002, 40.6% according to NUTRISCORE, and 59.4% according to the PG-SGA. There was a significant agreement between the results of the NRS-2002 and PG-SGA in a McNemar test (Kappa: 0.320, p = 0.008). NRS-2002 and PG-SGA tools offered greater sensitivity in terms of capturing more patients in the precachectic state than NUTRISCORE. Among these, the NRS-2002 is a shorter test, and thus, would seem to be more practical than the PG-SGA. Oncology, Malnutrition, Screening tools, NRS-2002, PG-SGA, NUTRISCORE.