In recent years, the need to adopt collaborative models within the supply chain has become increasingly evident, with the goal of improving planning and reducing inefficiencies caused by uncertain and fluctuating demand. This thesis analyzes the impact of adopting the Vendor Managed Inventory (VMI) model in supply chain management, comparing it with the traditional Material Requirements Planning (MRP) system. The objective is to assess the operational, managerial, and collaborative benefits resulting from the introduction of the VMI approach. The study examines the case of Lavazza, a company characterized by the absence of an internal warehouse and is based on a case study supported by two simulations: one in a single-supplier context and one in a multi-supplier context.