The aim of this thesis was to locate examples of the active involvement of major food retailers in innovation in food manufacturing, and to explain their reasons for this activity. Two characteristics of the food industry had an important bearing on the research: (1) slow growth in the demand for food and (2) the interaction between increasingly concentrated food manufacturing and retailing industries. The thesis seeks to improve existing theories of innovation, which do not embrace the possibility that retailers may make contributions to innovation in industries from which they obtain their supplies. Two principal investigation techniques were deployed. The first comprised in-depth interviews with major food retailers, which provided data on their purchasing policy for own label products, and on their technological activities. The second assessed the results of these policies by identifying the responsibility for major innovations in chickenmeat processing: a technological history was compiled from data drawn from several sources including industry experts and a literature search. Further studies indicate that the findings from the chickenmeat study are not a special case. The thesis contributes to theories of innovation by showing that food retailers with substantial in-house technological capability have played important roles in influencing technological change in food manufacturing. The need for restraint on the purchasing power of large retailers is an important policy issue. This thesis makes a contribution to the debate. Retailers' procurement policies which have been successful in stimulating innovation may also have wider relevance to other sectors of industry.