Surveys suggest that around 64% of retail shelf prices end in 9: The preponderance of 9-ending prices is not a new phenomenon and has been the subject of much comment and discussion over the past 70 years. Despite this broad interest, very few empirically based studies have been conducted in order to assess the effectiveness of the practice; no quantitative study can be found that has assessed the reaction of UK consumers toward 9-ending prices. In this paper we present the results of a large-scale store-based trial in which a selection of product prices were rounded up from the retailers' traditional 9-ending prices to round-pound prices. The results from this research suggest that the adoption of round-pound prices may be more effective, with trial sales increasing. The data yields an interesting insight into the effectiveness of the practice, and provides clear indication of the value further research in this area would bring.