Background: Nutrition screening tools are necessary to predict the risk of malnutrition for cancer patients. Objectives: This study aimed to investigate the validity of nutrition screening tools in identifying malnutrition among cancer patients.Materials and Methods: This cross-sectional study involved 175 oncology patients in Dr. Sardjito General Hospital. Malnutrition risk of participants was screened using Nutrition Risk Screening (NRS) 2002, Simple Nutrition Screening Tool (SNST), Malnutrition Screening Tool (MST), Nutriscore, and the Royal Marsden Nutrition Screening Tool (RMNST). Patient Generated-Subjective Global Assessment (PG-SGA) was used as a gold standard. Nutritional assessments, including Body Mass Index (BMI), Mid-Upper Arm Circumference (MUAC), albumin, hemoglobin, Total Leucocytes Count (TLC), and Hand Grip Strength (HGS), were used to evaluate nutritional status.Results: The NRS 2002, SNST, MST, Nutriscore and RMNST identified nutritional risk in 64.6%; 58.9%; 49.1%; 30.3%; 84.6%, respectively. The SNST obtained the highest level of AUC discrimination (0.8) compared to NRS 2002 (0.7); MST (0.7); Nutriscore (0.7); and RMNST (0.7). There was a significant association between nutrition screening with nutritional parameters except for TLC (P>0.005). Patients who were at risk of malnutrition had a lower average of objective assessment tools.Conclusion: All the nutritional screenings were valid to screen for malnutrition risk among cancer patients. Nutritional screening has a strong correlation with nutritional assessment. The lower risk detected by nutrition screening, the poorer the nutrition status measured by nutrition assessments.