Thirty ununited tibial fractures with a median time since injury of 18±9 months were treated by electrical stimulation using pulsing electromagnetic field therapy. Union was achieved in 25 cases (83.3%) in a median interval of 8.6±3.2 months. Patient age and gender, the presence of surgical hardware, length of disability, and the number of surgical procedures did not affect the outcome. Ununited fractures that appeared to be hypertrophic or sclerotic type radiographically, indicating a good blood supply to the bone ends, all healed. Treatment failures occurred only among lesions with a poor blood supply, and in necrotic or defective radiopraphic types. Pulsing electromagnetic field therapy is an effective treatment for ununited tibial fractures with good blood supply to the bone ends.