Background: A majority of older adults with cancer develop malnutrition; however, the implications of malnutrition among this vulnerable population are poorly understood. The goal of this study was to quantify the prevalence of nutrition related-symptoms and malnutrition among older adults with gastrointestinal (GI) malignancies and the association of malnutrition with geriatric assessment (GA) impairment, health-related quality of life (HRQoL), and health care utilization. Methods: We performed a cross-sectional study of older adults (≥60 years) who were referred to the GI Oncology clinic at the University of Alabama at Birmingham. Participants underwent the Cancer & Aging Resilience Evaluation survey that includes the abbreviated Patient-Generated Subjective Global Assessment of nutrition. Nutrition scores were dichotomized into normal (0-5) and malnourished (≥6), and multivariate analyses adjusted for demographics, cancer type, and cancer stage were used to examine associations with GA impairment, HRQoL, and health care utilization. Results: A total of 336 participants were included (men, 56.8%; women, 43.2%), with a mean age of 70 years (standard deviation, ±7.2 years) and colorectal cancer (33.6%) and pancreatic cancer (24.4%) being the most common diagnoses. Overall, 52.1% of participants were identified as malnourished. Malnutrition was associated with a higher prevalence of several GA impairments, including 1 or more falls (adjusted odds ratio [aOR], 2.1), instrumental activities of daily living impairment (aOR, 4.1), and frailty (aOR, 8.2). Malnutrition was also associated with impaired HRQoL domains; both physical (aOR, 8.7) and mental (aOR, 5.0), and prior hospitalizations (aOR, 2.2). Conclusion: We found a high prevalence of malnutrition among older adults with GI malignancies that was associated with increased GA impairments, reduced HRQoL, and increased health care utilization.