Sleep investigations were made in a laboratory using both traditional polygraphic methods and a portable home recording system (Medilog-Recorder 4-24). The evaluation was done by an automatic analysis. For the division into the particular sleep stages (classification of Dement and Kleitman) at least the diversions of 2 EEG and 1 EOG-channel were found to be necessary. As a further parameter the measurement of the pulse frequency was used. After the determination of the frequency-spectrum by the Fast Fourier Transformation a power spectrum was made in order to register the changes of voltages (in periods of 30 seconds) with a sample rate of 128 and a frequency resolution of 0.5 Hz. To evaluate the EOG, a band pass filter was used and after the determination of a level of 15 microV only activities over this value were regarded. Furthermore an automatic artifact detection was fit into the program. The activities of the EEG, the EOG and the pulse frequency were compared with the normal values of the stages and, after that, the particular sleep phases were determined.