This study examines the link between ownership structures and R&D activities in Canada. We hypothesize that highly concentrated ownership structures or the presence of controlling minority shareholders negatively affects R&D intensity of Canadian manufacturing firms. Our results show that the concentration of voting rights is negatively related to the level of R&D expenditure and R&D outcomes. Furthermore, we show that the level of separation between the voting and cash flow rights held by dominant shareholders of "Controlling Minority Structure" firms has a positive effect on R&D intensity but a negative effect on R&D outcomes. Copyright (C) 2010 ASAC. Published by John Wiley & Sons, Ltd.