Ninety-five percent of all urothelial carcinomas are located in the bladder and 5% in the upper urinary tract. Therefore, upper urinary tract urothelial carcinoma is relatively rare, with an incidence of 2.1-2.4 per 100,000 persons per year. Diagnosis is based on imaging, endoscopy, urine cytology and histology. Histopathological diagnosis of upper urinary tract tumours is essential for choice of therapy and follow-up, as both tumour grade and stage are important prognostic factors. Radical nephroureterectomy is the standard treatment, but has a direct effect on kidney function. For this reason, an increasing number of patients with low-risk tumours undergo kidney-sparing surgery to maintain kidney function. After kidney-sparing surgery intensive follow-up of the ipsilateral upper urinary tract is mandatory because of a five-year recurrence-free survival rate of 17-63%, depending on tumour grade. Current diagnostics all have their limitations. Nowadays, research focuses on improving diagnosis in order to be able to offer better individual treatment.