Background: Malnutrition is a predictor of cancer survival independent of cancer site. However, routine screening for malnutrition is underutilized. Advanced cancer accounts for 60% of cancer cases in developing countries of which approximately 52 % have malnutrition. This study aimed to describe factors associated with risk of malnutrition among patients with advanced cancer. Methods: We conducted a cross-sectional analysis of baseline data from patients with recently diagnosed advanced cancer included in a multidisciplinary patient navigator-led supportive care program in Mexico City (Te Acompañamos). At the time of enrollment in the program, patients completed a series of questionnaires including assessments of quality of life (FACT-G), various symptoms and the validated malnutrition screening tool (MST). Clinic and demographic characteristics were obtained from the patient chart. Descriptive statistics were used for analysis and factors associated with risk of malnutrition were analyzed by bivariate testing. Results: Between August 2017 and December 2022, a total of 601 patients were included. Mean age was 62 years (range 18-94), 57.2% were women, 56% had gastrointestinal and 28% gynecological malignancies. 72 % screened positive for malnutrition on the MST and 49 % reported nausea on FACT-G. Patients with an ECOG performance status ≥3 were more likely to screen positive for malnutrition (OR 5.9 95%CI 2.5- 13) as well as those with baseline nausea (OR 2.99; 95%CI 1.9-4.7). On the other hand, patients with active chemotherapy (OR 1.4 95%CI, 1.016-1.95) and those receiving antiemetic treatment with a single medication (OR 1.63 95%CI, 1.1-2.4) were more likely to have nausea. No other clinical or demographic characteristics were significantly associated with screening positive for malnutrition or reporting nausea, including gender, age, history of smoking or alcohol abuse, type of neoplasia, or oncologic treatment. Conclusions: Our results show that a high proportion of patients with advanced cancer are at increased risk for malnutrition and report nausea. Poor functional status and nausea were strongly associated with a higher risk of malnutrition, while receiving insufficient antiemetic medication was associated with increased odds of nausea. This suggests that appropriate treatment of nausea and nutritional interventions should be prioritized early in the management of patients with advanced cancer regardless of the type of cancer treatment in order to avoid malnutrition and improve patient well-being.