Congenital pseudarthroses and non-unions have been recognized as some of the most challenging problems in orthopaedic surgery. with a standard surgical procedure, such as bone grafting, nailing, plating or a combination of these, it was frequently failed to unit. After repeated surgical failures, amputation has been the main course. With the advent of an electrical control of osteogenesis, however, this dismal outlook is brightening. The earliest report of the use of electrical energy to directly stimulate bone healing seems to be in 19th century, but it was not reliable. In this century, the electrical properties of bone were first described by Yasuda et al in 1953. After then, several investigators have shown that the application of small amounts of the electrical current to bone stimulates osteogenesis at the site of the cathode. Clinical trials using various froms in the treatment of delayed union, non-union, and congenital-pseudarthrosis began early in the 1970's. Constant direct current, pulsed current, and electromagnetically induced current have all been used clinically to heal bone defects with varying degrees of success. But, to-this date it is unknown what is the mechanism of stimulating bone healiag with electricity, and which from of electricity is most efficient in stimulating osteogenesis. We have experienced direct current stimulation to promote osteogenesis in 9 cases of non-union and 4 cases of congenital pseudarthses of the tibia from august, 1978 to december, 1980. Of 9 non-unions, 7 (77.8%) achieved solid bony union. We had obtained bony union in 4cases of non-union only with the electrical stimulation. In 4 cases of congenital pseudarthses of the tibia, all cases achieved solid bony union with the electrical stimulation and bone graft, but in 3 cases, refractures were occurred. At this moment, our conclusions from this study are as followa. I. Direct current stimulation is one of the reliable methods inducing ostengenesis. 2. Regular follows-up and determination of the stimulator integrity are essential steps in the electrical stimulation. 3. Combined treatment with the electrical stimulation and bone graft have markedly improved the success rate. 4. In direct current stimulation of congenital pseudarthsis, the mechanically sound bony alignment, massive bone graft and protection using long leg brace seem to be mandatory procedures.