According to the current understanding, radiotherapy can enhance the effectiveness of cancer immunotherapy due to radiation-induced release of tumour-associated antigens. Here, we present a case with a metastatic urothelial carcinoma who received nivolumab and palliative radiotherapy to a residual tumour in the vagina and to a large metastatic visceral lymph node. The treatment resulted in a rapid and virtually complete response for the time being in all metastases and in the large parailiac tumour mass. Follow up continues. The presented case demonstrates that the combinatory treatment with radiotherapy and immunotherapy can result in an exceptional response for the benefit of the patient with urothelial cancer. To our knowledge, this is one of the largest metastatic masses to disappear with a combination of immuno-oncologic (nivolumab) and radiation therapies.