A retrospective study on complications especially related to operative or postoperative management was carried out in 1000 pacemaker implantations in 717 patients between September, 1972 and December, 1986. In 33 of our series (4.8%), 24 pacing failure occurred within two weeks of implantation. Flange-type leads had the highest incidence of complications. Wedging the electrode close to the longitudinal axis of the heart was found to be the best placing, assuming that the tip of the electrode and the section immediately adjacent were pointing downward. There were 6 cases of diaphragmatic pacing which could not be corrected through programming. No relation with the position of the electrode could be found. We recommend using bipolar pacing to lower the incidence of diaphragmatic pacing. We also had 9 patients with lead fractures (1.3%); these included 3 cases with silicone insulation breaks and 6 cases with wire fractures which occurred closely proximal to the area where the lead was fixed to the vessels. No relationship between the ratio of lead fractures and their brand was found. Five patients developed infections, all of them late postoperatively, over a period of 8 months to 5 years postop. Of these, there were 3 cases with postoperative prolonged hematoma at the pocket site, and 4 cases which had required lead repositioning because of pacing failure. The incidence of infection in our series was low when compared to previous reports, probably due to local use of one gram of Kanamycin during the operation and active chemotherapy performed short term postoperatively. To manage infection of the skin pocket, the pacemaker was removed and a new pacemaker was implanted in the opposite side. There was 7 early postoperative deaths. One of them due to cardiac tamponade caused by perforation of the cardiac wall by temporary electrode lead. The resustation was unsuccessful.