Increased concern for the transmission of infectious diseases, primarily AIDS and hepatitis, in the health care setting has led industry, government and the consumer to question the efficacy of protective clothing as it relates to virus transmission. There is a need for the development of standardized methodology under both dry and wet environments for assessing the biobarrier properties of protective clothing. Methodologies are in existence but they are mostly physical-chemical tests which have no correlation to biological tests. This paper describes a dry test method for relating the penetration of viruses to materials used in protective wear. The method uses an exposure chamber into which an indicator bacteriophage (ΦX174) is aerosolized and filtered through discs of material being tested. The phage is collected on a liquid carrier which is assayed for the presence of the indicator organism. The material can be evaluated according to the number of phages that penetrated the material.