Big Food Retail and Power: an economic-political estimation. Increasing market power of big retail into the agro-food supply chain depends on economic, institutional, cultural and policy factors. It is a multi-faceted issue that moves us to take into account not only the economic aspects but the social, policy, psychological and behavioural ones, too. This complexity can be handled trough different approaches: among them, the so called economic-political framework considers economic and behavioural factors together. This approach cannot leave aside from empirical estimation of market power presence. This paper is devoted to carry on a first-pass estimation of big retail market power in two Italian supply chains: olive oil and fresh vegetables. The econometric model proposed by Lloyd et al. (2009) allows us to estimate price transmission in the observed supply chains. Findings suggest that market power exists in the olive oil sector whereas the model does not significantly fit the data in the fresh vegetable sector.