The authors report their experience of 62 implantations of pacemakers in babies and small children by two different methods. The pleural cavity was chosen as the site of implantation in 22 patients aged 8 months to 10 years, weighing 4,2 to 26 kg, with a maximum follow-up period of 7 years. Reoperation was required in 11 cases: 6 replacements of mercury batteries, 5 electrode dysfunctions, 1 electrical leak syndrome and 1 septic complication. In the other 40 patients aged 24 hours to 17 years, weighing 2,2 to 37 kg, with a maximum follow-up period of 5 years, the pacemaker was implanted in the lumbar region. Reoperation was required in 4 cases; 1 pacemaker replacement for infection and 3 electrode faults with pacemaker replacement. It is 5 years since the authors abandoned the pleural cavity in favour of the lumbar area as the site of implantation in babies and small children. Programmable pacemakers with lithium power sources are preferred for their many well known advantages. The use of the pulse generators and the progressive improvement in the electromechanical properties of the pacing electrodes which have become more and more reliable, have made reoperation a rare occurrence. In addition, replacement of implanted material only requires a small lobotomy in the great majority of cases. Recurrent thoracotomies, difficult for the surgeon and dangerous to the patient, are thereby avoided.