Background: Hospitalized patients with advanced cancer experience a high symptom burden, which is associated with poor clinical outcomes and increased health care use. Symptom monitoring interventions are increasingly becoming standard of care in oncology, but studies of these interventions in the hospital setting are lacking. We evaluated the impact of a symptom monitoring intervention in hospitalized patients with advanced cancer. Methods: We randomly assigned hospitalized patients with advanced cancer who were admitted to the oncology service to a symptom monitoring intervention or usual care. Patients in both arms reported their symptoms (Edmonton Symptom Assessment System [ESAS] and Patient Health Questionnaire 4 [PHQ4], higher scores on both indicate greater symptom severity) daily via tablet computers. Patients assigned to the intervention had their symptom reports presented graphically with alerts for moderate/severe symptoms during daily oncology rounds. The primary endpoint was the proportion of days with improved symptoms for those who completed two or more days of symptoms. Secondary endpoints included hospital length of stay (LOS) and readmission rates. Results: From 2/2018-10/2019, we randomized 390 patients (76.2% enrollment rate); 320 completed two or more days of symptoms (median age=65.6 [range 18.8-93.2]; 43.8% female). The most common cancers were gastrointestinal (36.9%), lung (18.8%), and genitourinary (12.2%). Nearly half of patients (48.5%) had one or more comorbid conditions in addition to cancer. We found no significant differences between intervention and usual care regarding the proportion of days with improved ESAS total (B=-0.05, P=.17), ESAS physical (B=-0.02, P=.52), PHQ4 anxiety (B=-0.03, P=.33), and PHQ4 depression (B=-0.02, P=.44) symptoms. Intervention patients also did not differ from usual care with respect to secondary endpoints of hospital LOS (7.50 v 7.59 days, P=.88) and readmission rates within 30 days of discharge (32.5% v 25.6%, P=.18). Conclusions: For hospitalized patients with advanced cancer, this symptom monitoring intervention did not have a significant impact on their symptom burden and health care use. These findings do not support the routine integration of this type of symptom monitoring intervention for hospitalized patients with advanced cancer. The positive outcomes seen in previous studies of symptom monitoring interventions may not be reproduced in other patient populations and care settings. Support: UG1CA189823; Clinical trial information: NCT03396510.