In this article I assert that global cities are critical nodes in Global Commodity Chains because it is from them that producer services are provided. I explore forward linkages of producer service firms in Mexico City, showing that there are important service flows to companies responsible for the globalization of the `Mexican' economy. Based on this finding I also indicate reasons why Mexico City `on the map' of global cities and of Global Commodity Chains. I argue that both access to local knowledge and close contact to clients are key factors. A third issue dealt with is the position of Mexico City in the geography of governance of commodity chains. The analysis suggests that it is useful to break up global city functions into the management of the world economy and into its command and control, because Mexico City is certainly a place for the former, while the scope of influence exercised from the city is rather limited.