Background: Recent evidence supports a restrictive transfusion strategy in the majority of hospitalized patients, though transfusion practices for oncology patients remain highly variable. We evaluated whether use of a best practice alert for solid tumor oncology inpatients would result in more restrictive transfusion practices and impact patient outcomes. Methods: We conducted a retrospective, historical control analysis at a large academic hospital in Chicago, IL. We compared transfusion utilization among solid tumor oncology patients before and after implementation of a transfusion alert. Patients with active bleeding, hematologic malignancies and those undergoing surgical procedures were excluded. A best practice alert with clinical decision support encouraging use of a restrictive transfusion strategy (Hgb < 7 g/dL) was implemented 6/14 with phase-in completed by 9/14. We abstracted PRE intervention medical records of patients hospitalized from 5/1/13 to 4/30/14 and POST intervention records from 9/1/14 to 8/31/15. Readmission rates, incidence of ICU transfer and inpatient mortality were also compared using multiple linear regression. Outcomes were adjusted for age, gender, race, BMI, smoking status and Charlson comorbidity index. Results: 1296 total patients were included in the analysis (PRE, n = 685; POST, n = 611). There were no differences in age, gender, BMI or Charlson comorbidity index among cohorts, although the PRE cohort included more Caucasians (60.2% vs. 46.8%, p < 0.0001) and smokers (6.0% vs. 2.5%, p = 0.002). Packed red blood cells transfused per 100 patient-days were significantly lower in the POST-intervention cohort (3.8 vs. 6.4, p = 0.01). The POST-intervention cohort also had fewer 30-day emergency department visits (3.3% vs. 5.1%, p = 0.03). There were no significant differences in rates of 30-day readmission (34.6 % vs. 37.3%, p = 0.19), ICU transfer (0.5% vs. 1.1%, p = 0.08) or inpatient mortality (1.7% vs. 1.8%, p = 0.96). Conclusions: Implementation of a best practice alert among solid tumor oncology patients effectively reduced utilization of packed red blood cells without affecting patient outcomes.