Short term heart rate variability (HRV) was studied in 44 patients before, in 2 weeks and 2 months after coronary artery bypass grafting (CABG). Prior to surgery the patients were divided into 2 groups: with normal and substantially lowered HRV parameters. In 2 weeks after CABG lowering of HRV was registered in all patients. In 2 months parameters of HRV returned to preoperative level almost in all patients but did not exceed it despite restoration of coronary blood flow and improvement of myocardial contractility. Intergroup differences of characteristics of HRV remained the same as before CABG.