Root canal treatment of immature teeth is considered a great challenge for both the dentist and the patient. The thinness of the root canals walls and the lack of an apical barrier leads to unpredictable treatment results. Revascularization is a novel promising treatment option in the field of regenerative endodontics for management of immature necrotic permanent teeth. This case presents a successful treatment of an 8-year-old patient with a partially necrotic, immature permanent mandibular right first molar pulp by revascularization. The revascularization procedure was performed in two appointments using nitrous oxide sedation to reduce the child's anxiety during treatment. Following root canal disinfection with NaOCl, a triple antibiotic paste (ciprofloxacin, metronidazole, and minocycline) was applied into the canal. One week later, induction of bleeding, application of MTA, and tooth restoration using a stainless steel crown were performed. At the subsequent follow-up appointments (3, 9, and 16 months) the tooth was asymptomatic. After 2 years a radiographic assessment revealed complete periapical healing and apical closure, as well as increase in root length and dentin thickness. Conclusion: This case supports the evidence of revascularization as a biological treatment option for the management of necrotic young permanent teeth. Keywords: antibiotic paste, children, immature permanent tooth, nitrous oxide, partially necrotic pulp, regenerative endodontic treatment