The purpose of this article is to analyse the business changes that took place in the olive oil industry since the beginning of the Spanish political transition to democracy (around 1975) till 2010: merger processes, shareholders’ changes, commercial strategies, diversification, links with multinational groups and/or multisector organizations, modifications on the mechanisms of vertical coordination and in the structure of the production chain, etc. This analysis should be framed within the context of institutional, economic and social changes that took place in Spain along the aforementioned period, as well as the radical changes the food system underwent through, changes of consumption patterns, globalization processes and the growing power of distribution within the production chain. The studied period considers three different phases: Years previous to Spain joining the European Economic Community in 1986, from that moment till 1999, and finally the first decade of the 21st Century. Processes that led along those years to the present big Spanish oil groups are tracked. Among them we found companies of family origin that went through successive mergers, big second degree co-operatives that gather together many first degree co-operatives that entered into subsequent steps of the production chain and big multisector groups. At the closing date of this study, the effects of the economic crisis open a new phase of big changes that will facilitate that new business structures emerge through bigger merger processes.