Heart auscultation has one of the key roles in beside diagnosis, especially in patients with cardiovascular diseases. Sometimes, because of the human cars' low sensitivity, a problem emerges in the proper evaluation of heart sounds and murmurs of lower frequencies. Our study compared two stethoscopes, the classic acoustic stethoscope (Littmann 2120) and an electronic one with the sound amplifier and the noise filtering system (Medmax2) in 10 patients examined by 10 physicians. Significantly better detection of low frequency sounds was found in favour of electronic stethoscope (chi 2 = 17.9; p < 0.0001). It is concluded that the selective amplificator improves the stethoscope performance and has its place in everyday bedside practice, especially in departments of cardiology.