This paper provides an overview of recent research on estimating competitive interaction in food product categories. In particular, the focus of this review is on research using scanner data conducted at the disaggregate (e.g., store, chain or local market) level, including empirical studies of vertical (i.e., within-channel) conduct. Studies addressing the competitive interaction on price, as well as non-price variables (e.g., in-store display and feature advertising) are considered. The author first describes the methodologies available for measuring the competitive interaction between firms and then briefly summarizes recent empirical developments. Given the complexity of the interactions that take place in practice, it is argued that much of the richness of actual competitive behavior is lost in aggregate analysis. Competitive interaction is the result of a complex set of variables and influences-demand side factors, market and industry structure, firm "personality", and category characteristics all interact in a complex fashion to determine strategic behavior of retailers and manufacturers.