It is now well established that Diabetes Mellitus is associated with an increased risk to develop cancer. This relationship has been demonstrated not only in patients with overt Diabetes but also in those with impaired glucose tolerance and impaired fasting glucose. Insulin represents of course a crucial pathway in Diabetes Mellitus. On the other hand, insulin is also a proliferative and anti-apoptotic hormone which is able to bind both insulin and insulin-like growth factor receptor. Increased circulating concentrations of insulin and IGF-I are related to a higher risk of different kind of neoplasias such as breast, colonic, liver and pancreatic cancer. Many other conditions which coexist with Diabetes may represent risk factors for cancer development, while pharmacological compounds chronically used in patients with Diabetes could have a role in favoring or protecting against cancer. In patients with hormone-related cancers, the gonad blocking agents, commonly used as adjuvant therapy, results in a condition of hypogonadism and consequent insulin resistance. The ADA recommends lowering your risk of getting either diabetes or cancer by: (i) Reducing your weight if you’re carrying extra pound (ii) Eating healthy—including fresh vegetables, whole grains, fruits, low-fat or non-fat dairy products, lean meats, skinless poultry, fish, seafood and eggs—while watching the size of your portions (iii) Exercising, staying active (iv) Stopping use of tobacco products.