The paper aims to analyze the evolution of eco-innovative activity and strategies in the automotive sector over time. We suggest to use a patent count methodology tracking the development of selected technologies considered as promising ?green technologies? in the automotive sector. The paper contributes to an understanding of the industrial dynamics of the greening of industry and the economy , a theme little analyzed despite the huge and rapidly increasing literature on sustainable development and innovation. Our findings show that all the major firms in the automotive industry are diversifying their patent portfolios in order to generate competitive advantages derived from the introduction of eco-innovations, activities emerging in the 1990s and accelerating in scope and radicality in the end zeroes. All the firms are engaging in developing new alternative green trajectories to the existing dominant design, even though there is some variety in the strategic responses of the firm. The main firms within the industry do go green at a fairly similar pace hinting at important horizontal dynamics of the greening of industry, whereas focus has tended to be on the vertical greening dynamics. The analysis demonstrates the current fluid emerging stage of the greening of the economy but also illustrates that eco-innovation is already an important competitive factor globally.