We demonstrate a strong correlation between denaturation of bovine serum albumin (BSA) and the thermal conductivity k of aqueous solutions of BSA. When denaturation of BSA began, k dropped significantly. These results suggest that k, i.e., the ability of a protein to transport passively applied thermal energy, can be exploited to probe the conformational dynamics of BSA and potentially of other proteins. The technique of protein analysis demonstrated in this work is expected to be useful in micro-total-analysis systems because it is easier to miniaturize and to integrate into a device than is conventional differential scanning calorimetry analysis.