We present exptl. results on the liq.-side mass transfer characteristics of a structured packing (Mellapak). We have measured the product of the liq.-side mass transfer coeff. kL and the effective specific area ae by the NTU-HTU method in a column of 0.295 m internal diam. The column was operated in counter-current, O from a satd. water stream being stripped into air. In order to elucidate the effect of the specific area, we report results on 3 different packing types of specific geometric areas of 125, 250 and 500 m3/m2 (Mellapak 125.Y, 250.Y and 500.Y, resp.). The dependence of kLae on liq. load and gas velocity is qual. similar to that of random packings. Quant., however, the values of kLae for the structured packings studied in this work are higher than the values reported in the literature for random packings of the same specific geometric area under the same operating conditions. [on SciFinder (R)]