Self-adjusted Continuous Positive Airway Pressure or autoCPAP machines have been engineered to automatically adjust the pressure to maintain the upper airway patency. They can be used for titration or long-term home therapy. They have been developed to improve efficiency and compliance of CPAP treatment and the cost-effectiveness of titration and also to decrease the long waiting lists for manual titration. For the treatment, it is believed, but not demonstrated, that compliance may be increased by lowering the optimal pressure. Most machines are piloted by an algorithm based on detection of various combination of respiratory events such as apnoeas, hypopnoeas, snoring, inspiratory flow limitation or impedance. Several short-term studies have shown that autoCPAP reduces the indices of respiratory events and microarousals. In general, optimal CPAP determined automatically are identical or lower than evaluated manually by experienced technicians. However, the long-term benefits of auto-CPAP on compliance have not been determined and require further controlled clinical studies taking account not only compliance, but also sleep quality, quality of life, alertness and cognition for each autoCPAP. The cost-effectiveness of auto-titration versus conventional titration remains also to be established.