The paper analyzes some issues on the comorbidity between schizophrenia and cancer. Epidemiological studies have reported contradictory results, but it is certain that patients with schizophrenia are more likely to suffer from risk factors for cancer development, such as increased alcohol abuse, obesity, nicotine dependence and decreased physical activity. The paper gives guidelines for the treatment of cancer in patients with schizophrenia, and discusses possible interactions between chemotherapy and psychotropic drugs. Particular attention is paid to the use of antipsychotics which increase the level of prolactin, in view of the possible risk of breast and endometrial cancer in patients with schizophrenia.