During the last twenty years, the Spanish petrol market has undergone an intensive restructuration process; it has changed from being a state-owned monopoly to total liberalization and privatization. This liberalization process was accompanied by measures that facilitated the creation of a "national champion," the Repsol Group, which is a huge, vertically integrated company with a high market share in all the industry's segments. Using a dynamic model, this paper analyses whether the prices established by companies in the Spanish gasoline market, after the restructuration process, fits with a tacit collusion equilibrium. The empirical results show that a strategic behaviour of companies occurs and is compatible with a tacit collusion price strategy. So, the restructuration process does not seem to have introduced effective competition into the Spanish gasoline market. (C) 2009 Elsevier Ltd. All rights reserved.