Harmonic scalpel for the tissue cutting and coagulating is a replacement for the high frequency current, which can be connected with diverse complications. The principle is transforming of the electric power into mechanical longitudinal movement of the working part of the instrument, by piezoelectrical transducer situated in the hand piece. Between October 2000 and June 2001, one hundred and three patients were operated using harmonic scalpel. The average age was 50.2 years. Laparoscopic cholecystectomy, appendectomy and abdominal cyste fenestration was performed in 86, 12 and 4 patients respectively. In one patient laparoscopic cholecystectomy and abdominal cyste fenestration were done during the same operation. The average hospital stay was 2.8 days. Laparoscopic cholecystectomy, appendectomy and cyst fenestration using the harmonic scalpel are safe and successful operations, with good results and advantages of the minimally invasive surgery.