BACKGROUND: Individuals with substance use disorders (SUD) have high rates of chronic illness and readmission, yet few are engaged in addiction treatment. Hospitalization may be a reachable moment for initiating and coordinating addiction care, but little is known about motivation for change in the inpatient setting. OBJECTIVE: To explore the experiences of hospitalized adults with SUD and to better understand patient and system level factors impacting readiness for change. DESIGN: We performed a qualitative study using individual interviews. The study was nested within a larger mixed-methods needs assessment. PARTICIPANTS AND SETTING: Hospitalized adults admitted to medical or surgical units at an urban academic medical center who reported high-risk alcohol or drug use on AUDIT-C or single-item drug use screener. APPROACH: We conducted a thematic analysis, using an inductive approach at a semantic level. KEY RESULTS: Thirty-two patients participated. The mean age was 43 years; 75% were men, and 68% identified as white. Participants reported moderate to high-risk alcohol (39%), amphetamine (46%), and opioid (65%) use. Emergent themes highlight the influence of hospitalization at the patient, provider, and health system levels. Many patients experienced hospitalization as a wake-up call, where mortality was motivation for change and hospitalization disrupted substance use. However, many participants voiced complex narratives of social chaos, trauma, homelessness, and chronic pain. Participants valued providers who understood SUD and the importance of treatment choice. Patient experience suggests the importance of peers in the hospital setting, access to medication-assisted treatment, and coordinated care post-discharge. CONCLUSIONS: This study supports that hospitalization offers an opportunity to initiate and coordinate addiction care, and provides insights into patient, provider, and health system factors which can leverage the reachability of this moment.