Root canal perforation refers to communication between the root canal system and the periodontium. The management and prognosis of perforations are influenced by various factors, including the level of perforation, the size of the defect, and the timing of intervention. So, the purpose of this case report is to present a conventional non-surgical endodontic retreatment of maxillary left first premolar #24 with a subcrestal coronal perforation using bioceramic Putty. Body: A 22-year-old male was referred by his prosthodontist for retreatment of previous root canal treatment and perforation in access cavity in the left maxillary first premolar that was found during the preparation for post-placement. Tooth #24 responded positively to Percussion. Radiographic examination showed unacceptable obturation being short and with inadequate taper. Based on the clinical and radiographic findings, tooth #24 was diagnosed as previously treated with symptomatic apical periodontitis. A lateral subcrestal floor perforation was detected. The perforation location was visualized using dental operating microscope DOM. The access cavity was cleaned using 2.5% NaOCl and sterile saline solution and isolated with Polytetrafluoroethylene PTTE. Previous root canal filling was removed using hand and rotary instruments. A single visit root canal retreatment was done, and perforation was repaired using bioceramic putty. Patient was referred to fixed prosthodontic department for extracoronal restoration. A 4-month follow-up revealed that the patient was asymptomatic with no periapical or periodontal pathosis. Conclusion: The proper sealing of recent, small-sized, subcrestal perforation with MTA bioceramic putty provided favourable prognosis. DOM could be useful in management of iatrogenic root perforations.