Many patients with the obstructive sleep apnea syndrome (OSAS) look for alternative conservative or surgical therapies to avoid to be treated with continuous positive airway pressure. In view of the high prevalence and the relevant impairment of the patients lots of methods are offered which promise definitive cure or relevant improvement of OSAS. The working group "Apnea" in the German Society of Sleep Medicine and Research established a task force to evaluate the scientific literature on non-CPAP therapies in the treatment of OSAS according to the standards of evidence-based medicine. This paper summarizes the results of the task force. The data were unsatisfactorily for most of the methods. Sufficient data were available for intraoral appliances (IOA) and the maxillomandibular osteotomy (MMO). IOA's can reduce mild to moderate respiratory disturbances, MMO are efficient in the short and long term but are performed only in special situations such as craniofacial dysmorphias. Weight reduction and body positioning cannot be recommended as a single treatment of OSAS. Most surgical procedures still lack sufficient data according to the criteria of evidence based medicine. Resections of muscular tissue within the soft palate have to be strictly avoided. But even success following gentle soft palate procedures is difficult to predict and often decreases after years. Results in other anatomical regions seem to be more stable over time. Today combined surgeries in the sense of multi-level surgery concepts are of increasing interest in the secondary treatment after failure of nasal ventilation therapy although more data from prospective controlled studies are needed. There is no evidence for any other treatment options.