• With respect to the impact of internal integration on performance, we have to distinguish between the Logistics-Marketing and Logistics-Production interfaces. When companies achieve a high level of internal integration in the Logistics-Marketing interface, this level of internal integration does not lead to a better absolute performance. A high level of collaboration among Logistics and Marketing processes does not contribute to achieving cost, stock-outs or lead time reductions. This is true for the most and the least collaborating models. However, when a firm achieves a high level of internal integration in the Logistics-Production interface, its effect on performance depends on whether there is, or is not, external integration. The level of Logistics-Production integration leads to a better absolute performance, in other words, it contributes to achieving cost, stock outs and lead time reductions, when there is not external integration. However, when firms are externally integrated (for the most collaborating relationships), the level of external integration has such an important effect on performance that it annuls (or reduces) the effect of the Logistics-Production integration.