We study a nonisothermal gas absorption from a rising short gas plug using an approximation of the infinite dilution of absorbate and taking into account the effect of thermal diffusion on the rates of heat and mass transfer. Short contact time solutions of energy and mass conservation equations are obtained by a similarity method. It is shown that for absorption of ammonia and hydrogen chloride by water and water vapor by aqueous solution of LiBr neglecting effect of thermal diffusion results in overestimating the rate of mass transfer during absorption. (C) 2008 Elsevier Ltd. All rights reserved.