Infections remain a common complication of solid-organ transplantation and are a major factor of morbidity and mortality in renal transplant recipients. The incidence of infection in renal transplant patients is directly related to the net immunosuppressive effect achieved and the duration of the administration of immunosuppressive therapy. The major types of infections can be categorized according to the time post-transplant during which they occur: in the first month after transplantation post-surgical bacterial infections and in the period from one to four months post-transplant opportunistic infections, overall cytomegalovirus; late infections, beyond 6-12 months, are community-acquired infections. Opportunistic infections (like Pneumocystis carini, Listeria monocytogenes, and Aspergillus fumigatus) most frequently occur in the first 12 months post-transplant and can be modulated by prior exposures and the use of prophylaxis.