Aim: The purpose of this study is to describe the treatment of immature permanent incisors with apical periodontitis, based on the placement of an apical mineral trioxide aggregate (MTA) plug for apexification.  Materials and Methods: A 9 years old boy was referred to the restorative and dental material department at National Research Center in Egypt, with a chief complaint of recurrent abscess and pain associated with the fractured central incisors. The first visit was accomplished by using Sodium Hypochloride (NaOCL) irrigation and intra-canal medication with tri-antibiotic paste (TAP) without instrumentation. Follow-up was done up to 18 months using standardized digital radiographs Results: After 6 month, the patient was asymptomatic and the radiographic examination showed rounding of root ending and peri-apical tissue repair. Conclusion:  It was concluded that use of MTA as an apical plug in necrotized teeth with open apices is a valuable option and may replace long-term apexification, thus reducing the treatment time with regard to the healing of the periapical lesions and the apical closure.