© 2022Background: Cardiac rehabilitation (CR) is endorsed to improve cardiovascular outcomes in cancer survivors. The quality of CR-based research in oncology has not been assessed. Objectives: The aim of this study was to evaluate the quality of reporting and evidence from CR-based intervention studies in oncology and to explore associations between intervention participation and outcomes. Methods: Systematic searches of 5 databases were conducted (January 2020) and updated (September 2021). Randomized and nonrandomized studies evaluating CR-based interventions in adult cancer survivors during and after treatment were eligible. Independent reviewers extracted data using 2 reporting guidelines (Template for Intervention Description and Replication and Consolidated Standards for Reporting Trials Harms extension), risk of bias (ROB) assessment tools (Cochrane ROB 2.0 and Cochrane Risk of Bias in Non-Randomized Studies of Interventions), and a combined inventory (Tool for the Assessment of Study Quality and reporting in Exercise). A meta-analysis was used to explore pre-intervention/post-intervention differences for commonly assessed outcomes. Results: Ten studies involving data from 685 survivors were included. The mean quality scores for intervention reporting (Template for Intervention Description and Replication) and harms (Consolidated Standards for Reporting Trials Harms extension) were 62% and 17%, respectively. There was moderate-to-high ROB across nonrandomized (Cochrane Risk of Bias in Non-Randomized Studies of Interventions score: 25%) and randomized (ROB 2.0 score: 50%) studies. The mean standardized cardiorespiratory fitness was higher (0.42; 95% CI: 0.27-0.57), fatigue was lower (−0.45; 95% CI: −0.55 to −0.34), and percent body fat (0.07; 95% CI: −0.23 to 0.38) was not different in survivors completing CR compared with those not completing CR. Conclusions: CR-based studies in oncology have low-to-moderate reporting quality and moderate-to-high ROB limiting interpretation, reproducibility, and translation of this evidence into practice.