Abstract Empirical verification of the existence of a positive relationship between the ergonomic design of workplaces and achieved product quality levels is not easily established due to the difficulty involved in changing production procedures in a real workshop exclusively for research reasons. In this paper, a metalworking firm with ISO-9002 certification was selected, and its quality results were analyzed with respect to reprocessed and rejected parts after varying the initial work method on the basis of the results of and ergonomic evaluation by means of RULA. Statistical evidence of improvement in relation to reprocessed parts was confirmed, although not in relation to rejected parts. Relevance to industry Ergonomics and quality are both important aspects of management. Here we establish the positive relation between both: a reduction in ergonomic problems implies better quality records. To invest in ergonomics is worthy.