A 71-year old lady has been diagnosed with unresectable malignant melanoma of vagina since June 2017. At that time, she received high dose rate brachytherapy (7 Gy) followed by intracavitary radiotherapy (RT). Follow up MRI showed partial response of disease with residual tumor at vagina. Three months after completion of RT, she developed obstructive uropathy with acute kidney injury (Cr 3.99 mg%). Therefore, percutaneous nephrostomy (PCN) of the right ureter was performed with good recovery of renal function (Cr 0.98 mg%). The subsequent CT scan of chest and whole abdomen revealed local recurrence of vaginal mass with multiple liver and iliac nodes metastasis. She therefore was referred to us for seeking opinion regarding systemic therapy for metastatic malignant melanoma of vagina. The patient received nivolumab 200 mg (3 mg/kg) IV q 2 weeks with good tolerability. There was no immune-related adverse event occurred. After 4 cycles of nivolumab, the patient reported no more urine passing through PCN, and she was able to pass urine through the urethra. Subsequently, the PCN was successfully removed. Follow up CT scan after 4 cycles of nivolumab showed partial response (38% reduction). She hence continued 4 more cycles of nivolumab, and CT scan still showed further reduction of tumor (53% reduction). Here, we present the excellent response of anti-PD-1 immunotherapy in patient with uncommon site of malignant melanoma.