A best evidence topic was constructed according to a structured protocol. The question addressed was whether radiofrequency (RF) offers better results than stereotactic ablative therapy in patients suffering from primary non-small-cell lung cancer (NSCLC) unfit for surgery. Of the 90 papers found using a report search for RF, 5 represented the best evidence to answer this clinical question. Concerning stereotactic ablative therapy, of the 112 papers found, 10 represented the best evidence to answer this clinical question. A manual search of the reference lists permitted us to include seven more articles. The authors, journal, date, country of publication, study type, group studied, relevant outcomes and results of these papers are given. We conclude that, on the whole, the 23 retrieved studies clearly support the use of stereotactic ablative therapy rather than RF in patients suffering from primary NSCLC unfit for surgery. Indeed, stereotactic ablative therapy offered a 5-year local control rate varying between 83 and 89.5%, whereas the local control rate after RF ranges from 58 to 68%, with a short follow-up of ∼18 months. Furthermore, both overall survival and cancer-specific survival were better with stereotactic ablative therapy, with a 3-year overall survival ranging from 38 to 84.7% and the 3-year cancer-specific survival from 64 to 88%, whereas the 3-year OS, only reported in two studies, ranged from 47 to 74% for RF. Moreover, the post-interventional morbidity was superior for RF ranging from 33 to 100% (mainly composed by pneumothorax), whereas radiation pneumonitis and rib fracture, ranging, respectively, from 3 to 38% and 1.6 to 4%, were the primary complications following stereotactic ablative therapy. Hence, the current evidence shows that stereotactic ablative therapy is a safe and effective procedure and should be proposed first to patients suffering from primary NSCLC unfit for surgery. However, the published evidence is quite limited, mainly based on small studies of <100 patients. Moreover, so far there is no blind, prospective control, randomized study comparing these two techniques. Consequently, despite the encouragement of these preliminary results, they must be interpreted with caution.