We assessed adverse events and complications of bipolar radiofrequency induced thermotherapy of the tongue base (RFTB) in patients with socially unacceptable snoring (SUS) or obstructive sleep apnea syndrome (OSAS) and determine its acceptance and effectiveness when conducted under local anesthesia. This investigation consisted of (1) a prospective, open-enrollment study of 24 consecutive patients with snoring and OSAS at the tongue base level only (Fujita III), assessed by sleep endoscopy. Polysomnography, questionnaires, and visual analog scales (VAS) were used to assess outcome. (2) In addition, a retrospective review of 83 patients, who underwent RFTB (in 59 cases as part of a multilevel treatment), was performed to evaluate adverse events and complications. Twenty-two of the 24 patients completed postoperative questionnaires and VAS, and ten patients had postoperative polysomnography. Reduction in snoring (P = 0.0003), hypersomnolence (P = 0.002), and globus (P = 0.031) was significant. A positive trend in AHI (P = 0.001, n = 3) is shown in patients with moderate to severe OSAS. Concerning postoperative adverse events and complications, only two patients had a mild and transient tongue deviation directly after the procedure, which resolved within an hour postoperatively (adverse event rate 1.8%). No postoperative complications such as infections, abscesses, hematomas, or ulcerations of the tongue base occurred. This study demonstrates that bipolar RFTB in patients with obstruction at the tongue base only (Fujita type III) as visualized by sleep endoscopy is a safe and simple procedure under local anesthesia and can be effective in patients with SUS. No complications during this study were observed. Its effect on OSAS has been shown by other authors, although long-term effects are not stable. The RFTB can be considered as first choice treatment in case of snoring and mild OSAS in Fujita type III obstruction. In the case of moderate to severe sleep apnea, RFTB can be considered as an additional treatment.