Relaxation shrinkage in wool fabrics is normally measured after relaxation of the fabric in water or steam. Values obtained for relaxation shrinkage after wet relazation depend on the manner in which the fabric is dried. If the wet fabric is dried directly in an oven, the values for relazation shrinkage are low, but if the fabric is allowed to dry under ambient conditions before oven drying, values are high. Steaming procedures produce relaxation shrinkage values that are considerably lower than those obtained with wet relaxation. An interlaboratory trial conducted using thirteen commercial worsted fabrics has determined the repeatability and reproducibility of different methods for calculating the magnitude of relaxation shrinkage. The practical significance of the different methods has been assessed from garment trials where fabric shrinkage, resulting from making-up and from wear, was examined. A procedure for measuring relaxation shrinkage is recommended.