Objectives: We evaluated the use of Ilizarov circular external fixator in patients with pseudoarthrosis of the humeral shaft Methods: Thirty-five patients (25 males, 10 females; mean age 37.3 years; range 13-69 years) with pseudoarthrosis of the humeral shaft were treated with the Ilizarov circular external fixator. The mean interval between the primary treatment and application of the external fixator was 11.7 months (range 5-48 months). Mean follow-up was 39.2 months (range 24-80 months). Results: Union was achieved in all but one patient (%97.14), within a mean duration of 5.5 months (range 3-10 months). Although most of the patients experienced minor pin tract problems; these problems led to the removal of Schanz screws in only three patients. Radial nerve palsy developed in three patients during the early postoperative period, two of whom spontaneously recovered in three months. One patient with permanent palsy was treated by a triple tendon transfer. Conclusion: The Ilizarov external fixator is a reliable surgical alternative in the treatment of nonunions of the humerus, providing a rapid bony healing. It is the only treatment modality, enabling management of infected, defect pseudoarthrosis and in patients with extremity shortness and restricted shoulder and elbow range of motions.