Earthworms are known to play a significant role in the cycling of nutrients, formation of soil aggregates, and the incorporation of organic materials into the soil. However, there has been limited focus on how earthworm activity may mediate the transformation and distribution of organic pollutants within the soil and within soil aggregates. Since a significant portion of contamination occurs near the soil surface, the role of soil-dwelling organisms in their transformation/degradation is critical in understanding the fate of pollutants. Previous work has shown that earthworms contribute to the transformation and/or degradation of organic contaminants such as 2,4-6-trinitrotoluene through ingestion of contaminated soil particles and through modification of various soil properties and/or processes. The objective of this study was to determine the influence earthworms have on the transformation of TNT in soil and soil aggregates with different inherent properties (i.e. organic matter content, aggregate size distribution, etc). A three week incubation study using Eisenia fetida in two soils with different physical, chemical, and biological properties was conducted under laboratory conditions. The two soils were spiked with TNT at 100 mg kg-1 soil. The impact of earthworms on TNT transformation, soil microbial community structure, and aggregate size distribution will be discussed. The results for the two soils will be compared.