Apart from presenting a specific symptomatology, cancer of the bladder in some rare cases may present with a set of symptoms that at first sight seem unrelated to the tumour and that constitute the paraneoplastic syndromes. The importance of these paraneoplastic symptoms is represented by the fact that they may constitute the first sign of malignity, or may be the expression of a recurrence. Two rare cases of paraneoplastic hypercalcemia are reported, the literature is reviewed and the aspects of this rare pathology are analysed.