The safety and convenience of the transvenous approach to long-term endocardial pacing are well established, but its principal drawback is electrode displacement. The reported incidence of this complication varies between 3.0% to 36.7%, and is highest in the early post-implantation period before endocardial fixation of the electrode tip. Recently Brewster and Evans determined that the electrode displacement rate in 21 published series averaged 14.3%. However, the Inter Society Committee on Heart Diseases (ICHD) report on pacemakers states that a rate of early displacement greater than 5% calls for a critical review of results. The training and expertise of the persons inserting the pacemaker electrodes undoubtedly are major factors which determine the proper transvenous placement of permanent cardiac electrodes. This paper deals with our clinical experience of 353 patients who received permanent transvenous pacemakers during the period September 1, 1974 through March 1, 1979, with emphasis on problems and complications encountered and overall results.