Background: The use of oncology hospitalists has been shown to improve quality outcomes among hospitalized patients, though there is limited data on the use of hospitalists to care for patients with hematologic malignancies. The Hematology Malignancy Hospitalist Service (HMHS) was created in efforts to decrease patient volume on the primary hematology malignancy services at an academic hospital. Patients with active oncologic issues requiring specialty oncology management were cared for by oncologists on the primary leukemia, lymphoma, and myeloma services while patients with acute medicine-related issues were cared for by medicine hospitalists on HMHS. Methods: Criteria were established based on level of acuity and reason for admission to HMHS, which was comprised of a hospitalist attending and nurse practitioner. New admissions to HMHS were evaluated by the primary hematology malignancy service team as consultants and remained involved in patient care as deemed appropriate. Oncology attendings continued to care for patients on the primary leukemia, lymphoma, and myeloma services. We conducted a retrospective analysis from 6/28/21 through 6/30/22 excluding 1/2/22 to 2/6/22 when HMHS was paused due to the COVID Omicron surge. We compared length of stay (LOS), discharge before noon (DBN), and 30-day readmission rates of patients admitted to the HMHS service and those admitted to the primary services to assess for differences in outcomes. Results: There were a total of 95 (12%) admissions to HMHS and 669 (88%) to the primary services; 35.6% patients were white, 21.7% Black, and 10.3% Asian and 26.3% patients identified as Hispanic. The average age was 61.6 years. The average LOS in days was 9±9.09, 16.03±14.96, 11.41±14.88, and 12.68±11.40 (p = 0.005) for patients admitted to HMHS, leukemia, lymphoma and myeloma services, respectively. DBN on HMHS (6%) was similar to the leukemia service (6%) and improved compared to the lymphoma service (11%) and myeloma service (7%); p = 0.66. The 30-day readmission rate was also improved on HMHS (12%) compared to leukemia (21%), lymphoma (21%), and myeloma (18%); p=0.25. Conclusions: The development and implementation of a medicine hospitalist-driven hematology malignancy service significantly improved LOS without a negative impact on 30-day readmission rates when compared to a primary hematology malignancy service model. The addition of medicine hospitalists to the inpatient care of patients with hematologic malignancies demonstrates improvement in healthcare utilization. This is an important area for future evaluation to determine the most appropriate patients to admit to these services and assess other important outcomes.