The mechanism and kinetics of the reaction between aqueous solutions of COS and a sterically hindered primary amine, 2-amino-2-methyl-1,3-propanediol (AMPD), were investigated at 288-303 K using a stopped-flow technique. It was found that the reaction order according to power law kinetics was between 1.12 and 1.16 for an amine concentration range of 0.5 to 1.5 kmol m(-3). This overall order indicated that the thiocarbamate formation was complex and possibly involved a zwitterion intermediate. However, the experimental results can also be explained in terms of a single-step termolecular reaction mechanism. The kinetic rate parameters for aqueous AMPD solutions were obtained for 288 to 303 K and over the concentration range of 0.5 - 1.5 kmol m(-3) of AMPD.