The issue of whether vertical integration can raise market power is hotly debated because firms have a market power-related incentive to integrate vertically. Using a sample of U.S. food manufacturing industries, this “market power” motive is empirically tested in this study. Empirical analysis shows that forward vertical ownership integration (or vertical mergers) did not increase food manufacturers' market power in the final product market. The study, however, shows that both market structure and conduct significantly influenced market power in the food industries.