Presentation of a case-control study on 755 subjects with the purpose of defining whether the development of a neoplasia on any organ and of any histological type, either synchronous or metachronous, occurs more frequently in patients who already have vesical carcinoma (338 cases) versus other populations of similar epidemiological characteristics comprising subjects who do not present that condition (417 controls). The evaluation of the difference between both groups establishes a cause-effect relationship expressed in terms of an odds ratio of 2:11 which allows to claim that presence of a second neoplasia is more frequent in patients with vesical carcinoma (p < 0.001). The paper also includes a discussion on the distribution to organs and systems. Once the cases with urothelial site (renal pelvis, ureter or urethra) are excluded, prostate adenocarcinoma is the most frequent form associated to vesical carcinoma, followed at a distance by renal adenocarcinoma, epidermoid carcinoma of the larynx and bronchopulmonary carcinoma. Cumulative incidence of secondary neoplasias, including tumours diagnosed synchronically is 12% at 54 months.