Fouling due to crystallization on structured packings was studied in a 150 mm diameter column with 1800 mm packing height. A saturated solution of sodium chloride was used in countercurrent flow to dry air. The pressure drop increase of the column during operation and the ratio between dry pressure drop before and after the experiments are used to quantify the degree of fouling. The data obtained show clearly that, as expected, rough and porous materials such as ceramics and steel as well as wire gauze packings tend to a stronger fouling than others.