The primary aim was to find out if exercise reduces cancer-related fatigue in hospitalised oncology patients. Controlled trials of fatigue outcomes after exercise in hospitalised oncology patients were obtained by searching electronic databases. Two reviewers completed data extraction and quality assessment independently. Standardised mean differences and 95% confidence intervals (CI) were determined and a meta-analysis completed. Five relevant trials evaluated 269 hospitalised oncology patients. Meta-analysis of fatigue had an overall standardised mean difference of -0.27 (95% CI -0.62 to 0.08, p = 0.13) in favour of exercise. Evidence from a single trial supported the use of exercise in increasing muscle strength, and there were no significant between-group differences in psychological status and aerobic capacity. Though inconclusive, the findings demonstrate positive trends of reduced cancer-related fatigue in hospitalised oncology patients who exercise. Future adequately powered trials are required to provide evidence to confirm these positive effects.