Previous works applying hedonic price technique to determine the formation of auction prices of objects of art have found no conclusive result about the impact of auction houses on final prices. In these studies the object of art has been the unit, and influence of auction houses is analysed by testing whether auction house impact on price is significant or not within a framework of central tendencies. In order to focus on auction houses as a unit we have applied a benchmarking technique, DEA, developed for efficiency studies. Categorial and continuous variables are used as inputs and auction prices as outputs. Performance indicators are defined and calculated giving an insight into auction house differences impossible to obtain using hedonic price approach.