A method and apparatus by which lung deceases are identified uses computer analysis of sound signals that are picked up from various locations on the chest walls of a subject by a modified stethoscope. The modification includes a small microphone in one of the hoses of the stethoscope. Signals from the microphone are input to a computer such as a personal computer or PC for processing. The computer extracts from these signals features which are dominant for particular lung diseases. A classifier classifies these features, determines if the lungs are diseased, and identifies the disease.