A gender discrepancy exists in the incidence of both urothelial and kidney carcinomas, with more men presenting with these cancers than women. Men have a threefold greater risk of developing bladder cancer than women, but female gender has been identified as an independent adverse prognostic factor for both recurrence and progression of this disease. In particular, women with bladder cancer are often diagnosed with a higher tumour stage than men. Conclusive data on the influence of gender on outcomes of patients with upper tract urothelial carcinoma are currently lacking, although men seem to have a higher disease incidence, whereas survival outcomes might be independent of gender. Patients with renal cell carcinoma are more often men and they typically have larger tumours and higher stage and grade disease than women with this cancer. Smoking habits, tumour biology, occupational risk factors and sex steroid hormones and their receptors could have a role in these observed gender disparities. The majority of data support the theory that gender influences incidence and prognosis of urothelial and kidney cancers; men and women are different genetically and socially, making the consideration of gender a key factor in the clinical decision-making process. Thus, the inclusion of this variable in validated prognostic tables and nomograms should be discussed as a matter of importance.