Two investigations are reported. The first is a comparison of average prices for two cattle types within pairs of some major auction centres in Australia. Significant price differences existed in three of the four cases studied. The second is a study of the main determinants of price differences between auction selling centres through a case study of a large and small auction centre. The major factor explaining the price differences between the two auction centres was lot size. This factor also influenced price variation within auctions. The number of buyers purchasing cattle did not affect price levels.