We tackle the picker routing problem in mixed shelves warehouses. It is characterized by an order picker that starts from a central depot, walks
through picking and cross-aisles to pick the items of her/his picklist, and comes back to the depot. Due to the mixed-shelves storage policy, each item is available on multiple shelves. The objective of the problem is to select the locations (shelves) from where to pick each item of the picklist and design the tour that visits the selected locations. To solve the problem, we propose a Logic-Based Benders Decomposition that selects the locations in the master problem and designs the tours to visit the selected locations in the subproblem.