Introduction Vincristine is a vesicant chemotherapeutic agent which may leak from the vessel at the infusion site to the perivascular tissue and cause extravasation. Extravasation, a severe complication of chemotherapeutic drugs, can result in tissue necrosis that is considered an oncological emergency. Case report We aimed to report a case of a 29-year-old woman with ALL-B cell (Acute lymphoblastic leukemia) on maintenance chemotherapy regimen including vincristine, methotrexate, prednisolone, and 6-mercaptopurine (POMP). 48 h after administering intravenous vincristine, the patient experienced burning, pain and tenderness at the injection site (left hand – cubital cavity). Management & outcome 7 days after the onset of symptoms, the patient was hospitalized with a large brown lesion at the site. She was prescribed betamethasone cream, DSMO (Dimethyl sulfoxide) solution, and oral levofloxacin on his second day after admission. The lesion was completely improved 10 days after initiation of therapy and there were no serious problems. Discussion Due to the ineffectiveness of antidote therapy for the management of delayed extravasation of vincristine and beneficial effect of our clinical approach, it could consider for the management of similar cases with delayed extravasation following vincristine administration.