Over a three-year period, 3432 nosocomial infections occurred in a university hospital admitting 55,476 patients over a three-year period (6/100 admissions). A single system of surveillance was used, and overall monthly rates varied from 4-9/100 admissions with particularly high rates in the Newborn Intensive Care Unit (24/100). Annual rates greater than or equal to 10/100 admissions were found in major surgical services of Gneral Surgery, Neuro-Surgery, Thoracic Cardiovascular Surgery (TCV), Plastic Surgery and Urology; 1243 urinary tract infections (2.24/100 admissions/ accounted for 36% of the problem. The rate of urinary tract infections after catheterization was 13/100 procedures overall with unusually high rates for patients in Neuro-Surgery (37/100), Orthopedics (23/100), and Plastic Srugery (18/100). There were 524 nosocomial pneumonias (.94/100 admissions), and the rate was especially high (3.7/100) for patients admitted to the TCV service or for those placed on a respirator (3.4/100 patients). Identifying high risk areas and high risk procedures in a hospital is a practical starting point for infection control.