Sulzer EX packing is widely used in lab-scale separation studies owing to its high efficiency, low theoretical stage height and small pressure drop. In this work the three fundamental characteristic mass transfer parameters of this packing, effective gas-liquid contact area (ae) gas-film and liquid-film mass transfer coefficient (kG) and (kL) are measured in a 0.19 mm ID counter-flow absorption column using aqueous liquids. With end effects removed, the results show that the effective gas liquid contact area is independent of gas and liquid loads and reaches about 90 % of the geometric area of the packing. Correlations of the dimensionless gas and liquid phase mass transfer parameters are determined as ??hG = 0.048 ????G1.0 ????G0.33 and ??h L = 0.050 ????L0.4????L0.5.