This article describes the nonsurgical management of immature nonvital tooth with periapical lesion using Triple Antibiotic Paste. An 18 years old male patient presented with periapical lesion in relation to the tooth #21 and #22. Tooth 21 was an immature tooth. Triple antibiotic paste was placed as an intracanal medicament for a period of 6 weeks, Mineral trioxide aggregate was then placed as an apical barrier to a thickness of about 4 mm. Obturation of the remainder of the canal space was done after 48 hrs. The favourable clinical and radiographic outcome in this case demonstrated that Triple Antibiotic Paste (TAP) may be an efficient alternative to disinfect the root canals in nonsurgical management of nonvital immature tooth.