PURPOSE: To report the effectiveness of Kirschner wire fixation for the treatment of unstable tibial shaft fractures in children. MATERIALS AND METHODS: We analyzed 15 cases of pediatric tibial shaft fractures treated at our hospital with fixation using K-wire and followed up for more than 1 year from July 1998 to January 2002. The subjects included 11 boys and 4 girls. The ages ranged from 3 to 10 years at the time of injury, with the average age being 7.9 years. We examined the presence of angulation, leg length discrepancy, joint motion limitation, and complications. RESULTS: Bony fusion was obtained in all patients by an average of postoperative 9.5 weeks. At the time of last follow-up (by an average of postoperative 1 year and 4 months), anterior and posterior radiographs showed an average of 4.2degree angulation, and lateral radiographs showed an average of 4.4degree angulation. The affected leg was extended by an average of 3.7 mm compared to the opposite leg according to Bell-Thompson's radiographs. As for complications, infection was developed around the pin in 3 cases but treated with the administration of oral antibiotics and sterilization around the site without progressing to deep infection. We could not observe joint motion limitation, pain and difficulties related with discrepancy in leg length. CONCLUSION: We concluded that fixation using K-wire for children with tibial shaft fractures was a safe and effective method of surgery that could be performed easily, did not require secondary surgery to remove the wire, and showed sufficient stability after fixation.