The heterogeneous nucleation kinetics of ?-DL-methionine (?-DL-met) in aqueous solution was measured using direct determination of the rate of nucleation based on measurements of particle (crystal) counts appearing in a microdroplet as a function of nucleation time. The nucleation rates increase with increasing temperature when the supersaturation ratio is used as a measure of the driving force, but the dependence is less clear when the nucleation rates are plotted against the absolute supersaturation. The nucleation rates were found to exponentially increase with respect to the supersaturation ratio of DL-met. The measured nucleation kinetics follow trends expected from the classical nucleation theory (CNT), allowing approximate interfacial energies to be estimated by fitting the measured data to the CNT. The predicted interfacial energies and nucleation rates are consistent with results of similar species given in the literature.