Background: Electronic health record (EHR) integrated symptom monitoring using patient reported outcomes (PRO) has been associated with improved outcomes, including health-related quality of life (HRQoL), in cancer survivors. However, these improvements have been documented through reasonably high completion rates of PRO measures in predominantly non-Hispanic White patient populations using only English language assessments. This study aimed to 1) examine factors associated with the completion of PRO assessments and 2) test differences in referrals to cancer support services between PRO responders and non-responders in a cohort of cancer survivors with significant racial, ethnic, and primary language diversity. Methods: A retrospective analysis (October 2019-February 2021) was performed for patients who were assigned the My Wellness Check (MWC) program at a tertiary, comprehensive cancer center. MWC is an EHR-based PRO assessment and referral program that uses PROMIS computer adaptive tests for depression, anxiety, pain, fatigue, and physical function as well as a psychosocial needs assessment. MWC PRO questionnaire is available in English or Spanish based on patient preference. Demographic and clinical characteristics of patients were collected and incorporated in multivariable binary logistic regression model to examine factors associated with completion of the MWC PRO questionnaires. The frequency of referrals to cancer support services was compared by Chi-square test between MWC PRO responders and non-responders. Adjusted odds ratio (aOR) and 95% confidence interval (95%CI) were calculated. Results: Of the 5306 patients eligible to complete MWC PRO questionnaire, the majority were female (64.1%), White (86.9%), Hispanic (65.8%), English speaker (55.4%), and 46.0% were responders. Patients who were younger than 65 (aOR 1.39; 95%CI 1.22-1.59; p < 0.0001), female (1.23; 1.09-1.41; p = 0.0019), non-Hispanic/Latino (1.43; 1.25-1.64; p < 0.0001), living with partners ( = 1.28; 1.13-1.46; p = 0.0001), and receipt of active treatment (1.37; 1.18-1.58; p < 0.0001) were significantly associated with MWC PRO completion. Responders were referred to cancer support services more often than non-responders (16.6% vs 5.4%, p < 0.0001). Conclusions: Patient-level and clinical factors predict completion of PRO measures, and responders were more likely to have a referral to cancer support services. To optimize supportive care for ambulatory cancer patients, further research is needed to identify factors that can promote patient engagement, particularly in patients who are under-utilizers of such services.