The heat transfer performance and energy consumption of CO2 desorption from rich N-methyldiethanolamine (MDEA) solution were determined experimentally in a straight microchannel reactor. Nucleate boiling was found to be the dominant heat transfer mechanism in this experiment. The heat transfer coefficients were strongly dependent on the heat flux. The solution flow rate was the most influential factor on the heat flux, followed by desorption temperature, MDEA concentration, and CO2 loading. In addition, an empirical correlation was proposed to predict the experimental heat transfer coefficients.