OBJECTIVE:Assess the barriers and facilitators to implementing an exercise-based rehabilitation program in an acute setting for cancer survivors receiving treatment. METHODS:A qualitative study using individual semi-structured interviews and focus groups was completed with 25 clinicians working in oncology and 9 patients receiving cancer treatment who were purposively sampled at a tertiary hospital. Interviews were audio-recorded and transcribed verbatim with coding completed independently by two reviewers and confirmed by a third reviewer, followed by thematic analysis. RESULTS:The main theme was finding the 'right time' for rehabilitation. Exercise-based rehabilitation was seen as important to deliver in the acute cancer treatment setting but challenging due to patient factors such as feeling overwhelmed and health service constraints. Barriers and facilitators to acute exercise-based rehabilitation were raised under four sub-themes: attitudes, knowledge, convenience and resources. There was agreement among both patients and clinicians around the main themes. CONCLUSION:Implementing exercise-based rehabilitation in the acute cancer treatment setting is viewed as necessary but challenging to implement. Positive attitudes towards exercise-based cancer rehabilitation services from staff and patients in this study are at odds with current levels of service delivery. This study provides evidence for why this might be the case, and can be used to inform the design of future models of rehabilitation in the acute treatment setting to meet the needs of this patient group.