Surveillance for health care-associated infections (HAIs) using administrative data has received attention from health care epidemiologists searching for efficient means to track infections in their institutions. Several states are also considering electronic surveillance that incorporates administrative data as a means to satisfy an increasing demand for mandatory public reporting of HAIs. International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) discharge diagnosis codes have attributes that make them suitable for detecting HAIs; for example, they may facilitate automated surveillance, freeing up infection control personnel to perform other important tasks, such as staff education and outbreak investigation. However, controversy surrounds the appropriate use of ICD-9-CM data in detecting HAIs, and administrative coding data have been criticized for lacking elements necessary for surveillance. Administrative coding data are inappropriate as the sole means of HAI surveillance but may have value to the health care epidemiologist as a way to augment traditional methods.