The effects of pressure on the volumetric coefficient k(L)a and the interfacial area a in a counter-current packed column were studied in the pressure range 10(5) to 12 x 10(5) Pa. The method of gas/liquid absorption with chemical reaction was applied. The influence of the gas/liquid system on the interfacial area was also studied using three different chemical systems. It is shown that a and k(L)a decrease when the total pressure is increased. The authors have attempted to explain the differences between the values of a obtained under atmospheric pressure when the chemical system is changed.