We have developed a portable home sleep monitoring system using nasal airflow (NA), tracheal sound recordings (TSR), and electrocardiogram (ECG). NA was recorded by two thermisters. TSR was recorded by a microphone attached to the skin overlying the cervical trachea. Three kinds of signals were recorded with a cassette recorder. Thirty-seven outpatients who had sleep complaints were monitored during sleep at home using this recorder. Attachment of the pickups was performed by the patients themselves. Recordings were played back and analyzed by a personal computer to evaluate apnea episodes from TSR and R-R intervals beat by beat. This home monitoring system had labor-saving and cost-saving benefits and seemed to be a satisfactory technique for screening.