The objective of this paper is to analyse the complementarities and interrelationships between the different JIT purchasing practices which have extended in industrial markets in recent years. The incorporation of trust as an explicative element in a framework based on Transaction Costs Economics leads us to propose that the success of logistics-related JIT purchasing practices, which fundamentally transform the physical exchange process, depends on the implementation of additional practices which transform the way of governing and controlling the relationships and which support and rely on a co-operation climate. Empirical tests carried out over a sample of 148 Spanish auto components suppliers confirm this reasoning.