This study describes the treatment of an immature permanent tooth with periapical lesion which was treated with regenerative approach using platelet rich plasma (PRP). The root canal of immature human permanent tooth with periapical lesion was gently debrided of necrotic tissue and disinfected with 2.5% NaOCl, and then medicated with triple antibiotic paste comprised of ciprofloxacin, metronidazole, and tetracycline. When the tooth was asymptomatic, PRP and mineral trioxide aggregate (MTA) were placed into the root canal. Six months after PRP treatment, radiographical examination revealed resolution of the radiolucency and progressive thickening of the root wall and apical closure. Our findings suggest that PRP can be used for the treatment of immature permanent teeth with periapical lesion, as part of a regenerative endodontic treatment procedure.