Modern sleep medicine has been in existence for only 20 years and therefore has to be regarded as a comparatively recent field of specialization. For this reason it is not surprising that there are numerous new trends and developments concerning the treatment of sleep-related breathing disorders. This review focuses on developments in the treatment of obstructive sleep apnea (OSA) over the last 5 years.The review is based on a Medline bibliographic search using the key words 'treatment', 'obstructive sleep apnea' and 'sleep-related breathing disorders' and covers papers published since 1997, including references in these articles. In respect to conservative treatments the following important developments were found. Oral devices were shown to be effective in about 50-70% of patients with OSA, but at this stage it is not possible to predict in which patients successful treatment can be expected. As subjective compliance averages only about 50%, thermoplastic devices used as trial devices provide a reasonable alternative to reduce costs. Automatic continuous positive airway pressure (CPAP) units have been shown to cut costs when used for pressure titration in severe sleep apneics during the day or when used in so-called split-night procedures in appropriate cases. Nasal CPAP has proven to be effective in children, showing higher compliance rates than in adults. The development of mouth-pieces provides the possibility of using CPAP orally, e.g. after nasal surgery. Electrical stimulation of the tongue muscles shows promising preliminary results. Nevertheless, further research in this field is necessary. In the field of surgery, the most valuable development has been tissue reduction using radiofrequency energy, which has been shown to be effective and minimally invasive. Other fundamentally new surgical techniques have not been attempted within the last 5 years; instead, development in this area appears to be defined by a combination of previously known methods (so-called multilevel surgery) and optimized methods of patient selection. Such combined surgical procedures has achieved success rates of about 70%. Taking all these developments into account, CPAP therapy remains the gold standard for treatment of patients with OSA; yet the low long-term compliance rates of 60-70% have to be regarded as a major challenge warranting further effort.