Abstract There is currently a disconnect between the occupational hygienist and the epidemiologist in establishing quantitative relationships between exposure and resulting acute and chronic diseases. This disconnect is the result of a lack of standardization for assessing worker exposure to pathogenic biological agents. Specifically, there are numerous combinations of devices, analytical methods and units of measurement used in hygiene and epidemiological studies that prevent study to study comparisons and development of a uniform body of knowledge. Several recent reviews have concluded that occupational exposure limits for biological agents cannot be established due to this lack of standardization. The problem is exacerbated by the fact that most studies use area monitoring rather than breathing zone monitoring, a known source of error in defining worker dose. This review will use specific agents such as Legionella, Coccidioides, Endotoxin, Metalworking Fluid Mist, Flour Dust and Compost Dust to define the problem and suggest possible solutions.