A pendulum-type ballistic tester has been devised to measure the toughness of staples of wool. Using staples of varying tenderness from several types of wool, high correlations were found for the two sets of toughness values (and their ranking) obtained from the ballistic and a tensile testing machine. This and the ease and rapidity of the ballistic determination of the toughness of wool suggest its possible uses in the assessment of the quality of wool, in quality control work, and where the dynamic strength of wool for processing and end use is required.