Since 1981, the Centers for Disease Control (CDC) has been publishing Guidelines for the Prevention and Control of Nosocomial Infections as a useful reference tool in infection control. The extent to which practices recommended by CDC to reduce hospital-acquired infections have been successfully diffused and adopted were evaluated in a stratified random sample of 445 US hospitals that were sent a questionnaire in 1985. The data suggest that over 84% of infection control practitioner respondents (78% response rate) are aware of each guideline, although small hospitals (<50 beds) are least likely to be aware of the guidelines or to have reviewed them thoroughly. Adoption of the recommendations remains far from universal, ranging from 23% to 75% for 16 specific recommendations investigated. Smaller hospitals were significantly less likely than large hospitals to have adopted each suggested policy. Recommendations that carried Category I rankings were more likely to be adopted, as were those procedures that had cost-savings implications.