Sleep research and sleep medicine require the recording of biosignals during sleep and their subsequent analysis. The sleep recording is called cardiorespiratory polysomnography. Currently the analysis of the recorded signals is performed by experienced and certified sleep technicians. In addition to visual sleep scoring many attempts had been made to develop computer assisted sleep analysis. In order to develop a computer assisted sleep analysis a systematic database with sleep recording from 200 healthy subjects and of 100 subjects with selected sleep disorders of high prevalence had been compiled as part of a European Commission funded research project. This database was the start for a normative polysomnography database and for the development of a computer based sleep analysis. The computer based sleep analysis is available as an internet service and is now used by many sleep centers for sleep research questions and clinical sleep evaluation in patients with sleep disorders.