OBJECTIVE: Despite several studies on the effects of exercise training on inflammatory biomarkers in patients with breast cancer, no earlier study has systematically summarized their findings. Current systematic review and meta-analysis has been done on earlier clinical trials in this topic. METHOD: Relevant studies published up to August 2021 were searched through PubMed, MEDLINE, SCOPUS, EMBASE, and Google Scholar using predefined keywords. Studies that examined the effect of exercise training on inflammatory biomarkers in adult women with breast cancer were included. RESULT: A total of 18 studies were included. Combining 11 effect sizes, exercise training significantly reduced CRP level (WMD: -0.55; 95% CI: -1.10, -0.01). However, it had no significant influence on serum TNF-α (WMD: -0.40; 95% CI: -1.30, 0.50) and IL-6 concentrations (WMD: -0.05, 95% CI: -0.53, 0.43) in 8 and 15 studies, respectively. Pooling 7 effect sizes, we failed to find significant changes in IL-8 following exercise training (WMD: -0.65, 95% CI: -1.57, 0.28). Moreover, we reached no significant findings for serum levels of INF-ɣ (WMD: -2.66, 95% CI: -7.67, 2.36), IL-1β (WMD: 0.03, 95% CI: -0.26, 0.21), and IL-10 (WMD: -0.70, 95% CI: -2.92, 1.52). Based on subgroup analyses, best findings were reached in long-term intervention and after concurrent training. DISCUSSION: Chronic inflammation is hypothesized to be associated with breast cancer development. We found significant reduction in CRP level following exercise training, which was more considerable after concurrent aerobic and resistance training and in long-term intervention. No significant changes were seen in serum levels of TNF-α, IL-6, IL-8, IL-10, INF-ɣ, IL-1β following exercise training. Further studies are needed to find more details.