domain reflectometry (TDR) technique. The relationship between thermal conductivity and water content (θv) was measured for both aggregated (<2 mm) and non-aggregated (<0.1 mm) loam and clay loam soils using two different experimental approaches: continuous vs. non-continuous measurements. The results from the continuous measurement showed that thermal conductivity was significantly higher in the non-aggregated soils than in the aggregated soils at intermediate water contents. This is explained by the formation of intra-aggregate pores in aggregated soils that decreases the contacts and heat flow between aggregates. Alternatively the non-aggregated soils have a relatively uniform pore system that enhances bridging between neighboring particles through pore water, thus improves heat conduction. For the non-aggregated soils, relatively larger bulk density increase during the drying process also contributes to the greater thermal conductivity than that of aggregated soils. The results from the non-continuous approach, however, showed similar thermal conductivity values for the aggregated and non-aggregated soils, which was possibly caused by aggregate reformation in no aggregated samples during soil mixing and packing.