178 Background: Patient-reported outcomes measurement is recommended to improve care delivery. Toxicities are important to study given their impacts on treatment completion. We captured patient-reported toxicities in community-based oncology practices and identified toxicities associated with excess health care service use. Methods: We surveyed newly-diagnosed patients who completed their first chemotherapy cycle at 5 community practices. Exclusion criteria were prior cancer history, non-English speakers, psychiatric diagnosis, and clinical trial participation. At the second cycle return visit, patients completed a questionnaire that measured the severity of nausea, vomiting, diarrhea, constipation, mouth sores, intravenous catheter problem, pain, fever/chills, extremity edema, and dyspnea. These were rated on a 5-point scale (1= did not experience to 5 = very severe). Patients also reported unscheduled oncologist visits, emergency department visits, or inpatient hospitalization. Results: Of 117 eligible patients, 106 (91%) participated. Most patients (98%) were white, 25.5% were male, and the mean(SD) age was 60 (11) years. The most frequent diagnoses were breast (43%), lung (21%), colorectal cancer (13%), and non-Hodgkin lymphoma (13%). Between cycle 1 and 2, frequent severe or very severe toxicities were nausea (30%), pain (18%), diarrhea (9%), and mouth sores (9%). 15% of patients had an unscheduled oncologist visit, 18% had an emergency department visit, and 9% of patients were admitted. Nausea (11.3%) and diarrhea (6.6%) were frequent reasons for unscheduled oncology visits; nausea and pain (both 5%) for emergency department visits, and; pain and dyspnea (both 2%) for hospitalization. Conclusions: Patient-reported toxicity monitoring is feasible and informative in community-based oncology practices. Despite widespread antiemetic use, nausea is a pervasive problem for newly-treated patients and drives excess service use. Pain assessment and management strategies are needed to reduce emergency department visits and hospitalizations.