Objective: This study aimed to perform a systematic review, in order to investigate the effects of a non-pharmacological therapy (TENS) in cancer pain through clinical trials. Methods: 208 studies were identified in those databases, after title and abstract analysis, 198 studies were excluded. A total of 10 studies were selected for full-text analysis. Six papers were excluded based on exclusion criteria, resulting in 4 studies included for this systematic review. Standardized forms were used for analysis. Risk of bias was assessed with the “Cochrane Collaboration” tool, which assess five different domains. Results: Selected studies were randomized clinical trials that investigated the use and/or feasibility of transcutaneous electrical nerve stimulation on patients suffering from cancer-related pain. However, studies had a high divergence regarding sample, methodological design, treatment parameters, and outcomes assessed. Two studies, one involving pain related to breast cancer treatment and other investigating TENS on palliative care, showed no difference from placebo. Other two manuscripts report positive effects on pain, one on cancer-related bone pain and a second on cancer-related postoperative pain. Conclusion: We concluded that there is no sufficient evidence showing that TENS is effective for treating cancer-related pain. Additional research, with larger sample sizes, sample homogeneity and randomization and that investigate potential side effects is needed for a better assessment of TENS viability for the treatment of cancer-related pain.