Twenty-four children 15 kg or less in weight (range 2.8-15 kg) underwent implantation of a permanent pacemaker using the transvenous technique of lead placement. During a follow-up period of 2 months to 6 years 1 month (median 3 years 6 months) eight children suffered complications, six of which necessitated reoperation. These included: lead fracture in two, infection in two, transient myocardial dysfunction in one, generator migration in one, premature battery depletion in one, and threshold rise in one. A loop of redundant ventricular lead positioned in the atrium at the time of implant is successfully unravelling in all children. One child died during the follow-up period of a pneumonia unrelated to her pacemaker. The other children are growing and developing normally and the cosmetic appearance has proved acceptable in all cases.