Factors associated with wounds and bruises in lambs killed at Longbum Freezing Co. Ltd have been investigated. There were no statistically significant differences in the prevalence of lesions between groups of animals of different sex and grade. When groups of unwashed lambs were compared to groups of washed lambs, from lines which were passed for slaughter by Ministry of Agriculture and Fisheries' Inspectors, there was a highly significant increase in the prevalence of bruising in the washed animals. There was also a statistically significant decrease in the rate of contamination in the washed group. However, closer examination of the individual lines in the washed group revealed that this apparent effect was essentially due to two of the nine lines in the study. These problems are discussed in relation to the difficulties a regulatory authority has in making the correct decisions in relation to washing stock.