Objective To discuss the indications,surgical techniques and prognosis of pediatric Monteggia fractures treated with elastic stable intramedullary nail (ESIN).Methods In the period between January 2005 to December 2012,27 children with Monteggia fractures were treated with ESIN and completely followed up by authors.They were 15 boys and 12 girls,aged from 4.0 to 13.3 years (average,7.3 years).The injury affected 12 left sides and 15 right sides.According to the Bado classification system,19 cases were of type Ⅰ,5 of type Ⅲ and 3 of type ⅣV.In Bado types Ⅰ and Ⅲ,the ulnar fractures were treated with closed reduction and internal fixation using ESIN.In 2 cases of Bado type Ⅳ,fractures of the ulna and radius were fixated with ESIN.In another case of Bado type Ⅳ,the ulnar facture was fixated with plate and the radial fracture with ESIN.The radiohumeral joints were treated with open reduction in only 2 cases,and with closed reduction in the rest.The reduction was evaluated by the postoperative X-ray films and the therapeutic outcomes were assessed by the Bruce-Harvey-Wilson evaluation system.Results The follow-up period ranged from 10 months to 31 months (average,18 months).All fractures united without infection,myositis ossificans,Volkmann ischemic contracture or skin irritation.Complete healing (mature callus and medullary cavity recanalization) was achieved after 12 to 33 weeks (average,20 weeks).According to the postoperative radiographs,22 cases were considered excellent and 5 cases good.According to the Bruce-Harvey-Wilson scoring system,26 cases were considered excellent and one good.Conclusion Since the technique of ESIN is simple,practical and minimally invasive,and leads to fewer complications,it is an effective treatment for pediatric Monteggia fractures,especially after failed conservative management and for those associated with Gustilo type Ⅰ open wound. Key words: Ulna fractures; Fracture fixation, intramedullary; Child