Introduction: Surgical gowns are designed to prevent or minimize transmission of blood and pathogens between patients and hospital personnel. During prolonged procedures, a gown will probably be presented with repeated challenges of blood and other liquids. These multiple insults may alter the fabric's permeability to subsequent blood contact. Methods: In this study, a pressing-leaning simulator was used to quantify changes in fabric permeability to blood after surgical gowns were prewetted with anticoagulated or coagulating blood. Results: Of the five commercially available gowns tested, contact with blood for 1 hr before application of an external pressure increased permeability for two gowns, decreased permeability for two gowns, and did not alter the permeability of one gown (as compared with test conditions in which the fabrics were not prewetted with blood). These data indicate that at least in some cases prolonged contact with blood increases the amount of blood penetration on application of an external pressure, such as may occur during a pressing or leaning motion. Conclusion: Because increased fabric permeability results in an increased risk of skin contact with liquid-borne pathogens for gown users, a major criterion in the design and selection of a gown should be its ability to resist blood penetration for prolonged periods. © 1993.