A growing body of evidence suggests that systemic inflammatory response (SIR) in the tumor microenvironment is closely related to poor oncologic outcomes in cancer patients. Over the past decade, several SIR-related hematological factors have been extensively investigated in an effort to risk-stratify cancer patients to improve treatment selection and to predict posttreatment survival outcomes in various types of cancers. In particular, one readily available marker of SIR is neutrophil-to-lymphocyte ratio (NLR), which can easily be measured on the basis of absolute neutrophils and absolute lymphocytes in a differential white blood cell count performed in the clinical setting. Many investigators have vigorously assessed NLR as a potential prognostic biomarker predicting pathological and survival outcomes in patients with urothelial carcinoma (UC) of the bladder. In this paper, we aim to present the prognostic role of NLR in patients with UC of the bladder through a thorough review of the literature.