After the 1982 Beltwide Conference, Cotton Incorporated (CI) distributed a "standard cotton dust" to allow researchers to compare in vivo and in vitro bioassays for byssinogenic activity. Our role at the Southern Regional Research Center (SRRC) was to chemically characterize the dust and lint fractions. Energy dispersive X-ray fluorescence methods were used for elemental analyses, wet chemical techniques for proximate analyses, and scanning electron microscopical methods for analyses of surfaces. Results of these analyses will be presented and compared to results with other important cotton dusts being used in bioassay research.