There is limited literature on the roles and tasks conducted by oncology social workers (OSW) who work with cancer patients in inpatient units. The purpose of this study was to delineate the roles reported to be significant to practice among OSWs who practice in inpatient settings and to identify the domains into which these roles fall. The data used in this secondary data analysis were collected in a large national study of OSWs to delineate the roles and tasks across all cancer settings. The sample extracted for this study were 240 OSWs who endorsed providing direct care to cancer patients in inpatient settings. Exploratory factor analysis revealed eight factors made up of 34 tasks. The roles were aligned with three of the four service areas in the Association of Oncology Social Scope of Practice and seven of the nine competencies set forth by the Council of Social Work Education. The findings can be used to enhance communications about the roles of inpatient OSWs across OSW constituencies, increase awareness of the role supervision and consultation to ensure equitable and just practice, enhance social work coursework to prepare students to work in healthcare inpatient settings, and in future research.