Background: Among patients receiving chemotherapy, symptomatic adverse event monitoring with electronic patient-reported outcomes (ePRO) is associated with improved clinical outcomes, satisfaction, and compliance with therapy. Standard approaches for ePRO implementation are not established warranting evaluation in community cancer practices. Objective: Evaluate implementation of ePRO symptom monitoring across a large multi-site community oncology practice network. Methods: Patients initiating a new systemic therapy at one of 210 practice sites in the Texas Oncology Practice were invited to use in the Navigating Cancer ePRO platform, with rolling implementation from July-December 2020. Participating patients received a weekly prompt by text message or email (patient choice) to self-report common symptoms and well-being via web or smartphone. Severe self-reported symptoms triggered a real-time notification alert to nursing triage to address the symptom. Enrollment and compliance were systematically tracked weekly with evaluation of barriers and facilitators to adoption and sustainability. Results: 4375 patients planning systemic treatment enrolled and participated, with baseline characteristics are shown in Table 1. 73% (1841/2522) of enrolled patients with follow up completed at least one ePRO assessment, and among these individuals, 65% (8762/25061) of all available weekly ePRO assessments were completed. Over a 10-week period, compliance with weekly symptom reporting declined from 72% to 52%. Patients on oral therapy had higher compliance rates overall. Barriers currently being addressed include lack of a second reminder text/email prompt, inconsistent discussion of reported ePROs by clinicians at visits, and COVID-related changes in workflow. Facilitators included patient and staff engagement on the importance of PROs for symptom management. Conclusions: ePROs can be effectively implemented in community oncology practice. Utilization of ePROs is high, but diminishes over time without attention to barriers. Ongoing work to address barriers and optimize compliance are underway.