KRAS belongs to the RAS family of oncogenes and is important in the development and progression of a variety of cancers. KRAS can harbor oncogenic mutations that yield a constitutively active protein. The frequency of KRAS gene mutations in upper tract urothelial carcinoma is low (5%). In the context of urothelial carcinoma of the bladder, mutations in the KRAS gene do not appear to be predictors for recurrence-free, progression-free and disease-specific survival according to some studies. The prognostic and predictive role of KRAS mutations in upper tract urothelial carcinoma needs to be further elucidated.