Post-transplant diabetes mellitus (PTDM) is a frequent and serious complication after kidney transplantation. Its ethiopathogenesis is multifactorial and includes the immunosuppressive regimen, the ethnicity, older age and the body mass index. Among these, calcineurine inhibitor and steroid use seems to have outstanding relevance. Both patient and graft survival is significantly reduced in recipients affected by PTDM. The main clinical aspects of transplant recipients with PTDM are patient and graft survival rate, infections, cardiovascular complications and late complications of diabetes that include nephropathy, neuropathy, retinopathy, micro-macroangiopathy and bone disease. The main stages of PTDM prophylaxis and treatment are: to identify patients at risk pre-transplantation; to control modifiable risk factors post-transplantation; to control hypertension and lipid profiles and a strict metabolic control. Insulin treatment is indicated mainly in thin patients and oral hypoglycemic agents should be reserved for overweight patients. Transplant centers are currently accepting higher risk candidates for post-transplant complications; therefore, attention needs to shift to the prevention and the control of complications, such as PTDM, because they can lead to a poor quality of life and an increased mortality in patients with functioning grafts.