This study is mainly concerned with an examination of the wholesale and retail margins in the beef marketing industry. In order to describe these margins adequately, considerable attention has been paid to the operational characteristics of the industry, to supply, and, to a lesser degree, to consumption. The study was limited to the years 1935 to 1957 inclusive. All price data included refer to medium quality, light and heavy steers, and heifers and to the equivalent carcass grades. The study is confined to the beef marketing industry of Manitoba, more particularly to the Winnipeg market. The supply side of the industry is first dealt with in detail, followed by an intensive examination of the farm price, the wholesale and the retail margins. On the basis of evidence obtained during the study, it was found that the wholesale margin tended to rise as volume increased. On the other hand, the retail margin, in the prewar period, varied inversely with supply. There was some evidence to support the belief that, when supplies of meat were small, inter-packer competition resulted in over-bidding and therefore smaller than "normal" packer margins... It was also found that consumer demand curves and retail and wholesale derived demand curves moved upwards to the right in the postwar period as compared with prewar...