The essay aims to provide Italian readers with some essential elements of collective agreement in the Spanish industrial relations system, pointing out the presence of two models: the so called sta-tutory collective agreement, with erga omnes effects and the extra-statutory collective agreement ruled by the Civil Code. On the other hand, the paper deals with the relationship between law and collective agreement as sources. The Author goes then into the main features introduced by the recent reform and tries eventually to make some reflections by way of comparison with the Italian system.