BACKGROUND: Nutritional impairment is associated with treatment toxicity and worse overall survival in patients with cancer. We aimed to (1) evaluate the association of nutritional impairment with psychological health and quality of life (QOL) and (2) examine which measures of nutrition had the strongest association with psychological health and QOL among older adults receiving cancer treatment with palliative intent. METHODS: This secondary analysis was performed on baseline data from a nationwide cluster randomized clinical trial (ClinicalTrials.gov identifier: NCT02107443; PI: Mohile). Adults age ≥70 with advanced cancer and ≥1 geriatric assessment (GA) impairment were enrolled from 2014 to 2017. In line with geriatric oncology standards, we defined nutritional impairment as Mini Nutritional Assessment Short Form (MNA-SF) ≤11, body mass index (BMI) <21 kg/m2, or >10% involuntary weight loss in the past 6 months. We conducted multivariable linear regressions to evaluate the association of nutritional impairment with each measure of psychological health and QOL: Geriatric Depression Scale (GDS-15, range 0-15), Generalized Anxiety Disorder-7 (GAD-7, range 0-21), NCCN Distress Thermometer (NCCN DT, range 0-10), and Functional Assessment of Cancer Therapy-General (FACT-G, range 0-108). Analyses were adjusted for patient demographics, clinical characteristics, and GA. RESULTS: Among 541 patients, the mean age was 77 (range 70-96) and 60% had nutritional impairment. Mean baseline scores: GDS-15 3.1 (SD 2.7), GAD-7 2.9 (SD 4.0), NCCN DT 2.9 (SD 2.7), and FACT-G 80 (SD 15). In the adjusted model, compared to those with no nutritional impairment, older adults with nutritional impairment had greater depression (β = 0.79, 95% CI 0.36-1.23) and anxiety severity (β = 0.86, 95% CI 0.19-1.53), and worse QOL (β = -6.31, 95% CI -8.62 to -4.00). Of the measures of nutrition, MNA-SF ≤11 demonstrated the strongest associations with depression, anxiety, distress, and QOL. CONCLUSION: Nutritional impairment is associated with impaired psychological health and worse QOL. Clinicians should use the MNA-SF to screen older adults for nutritional impairment and offer tailored supportive interventions.