We studied the incidence, trends and clinical correlates of infections following kidney transplantation in the United States Renal Data System over the years 1995-2003 in 46,471 adults with Medicare primary coverage at the time of their first kidney transplant. The incidence of most infections has declined only slightly since 1995 but infection with cytomegalovirus significantly declined while that with hepatitis C significantly increased. Relative frequencies of different types of infections (bacterial, viral, fungal and parasitic) were relatively constant, both during early and late periods following transplant. Using the Cox proportional hazards analysis we found that the clinical correlates for post-transplant bacterial and viral infections included older age, female gender, diabetes as the cause of end-stage renal disease, deceased (vs. living) donor source, time on dialysis before transplant, hepatitis B and C viral pre-transplant serologic status and pre-transplant donor-recipient cytomegalovirus serology. Our study shows that despite identifiable risk factors, the incidence of most post-transplant infections has changed little since 1995.