The gas and liquid resistances to mass transfer were determined for two polypropylene packings placed in an experimental crossflow tower. The results were then compared with corresponding counterflow data as well as with several counterflow mass transfer correlation equations. The liquid-side mass transfer properties of the two packings proved to be nearly identical for both types of operation, whereas Onda's counterflow gas-side equation failed to yield accurate results with either mode of operation or packing type. Crossflow air pressure drop gradients were also evaluated, with conflicting results. Includes 24 references, tables, figures.