Lean manufacturing tools have been applied for several years to improve companies' internal logistics. However, lean warehousing (LW) is a relatively new subject in logistics, and for this reason there is still a lack of academic literature and implementation experiences about it, in particular regarding the manner of selecting the right indicators tomeasure the warehouse's leanness, taking into consideration the firm's own objectives and context. This paper's objective is to identify key indicators for facilitating the objective setting, monitoring and LW implementation, and then propose a lean warehousing key performance indicator (warehouse's global leanness (WGL)) by implementing an innovative lean warehousing scorecard. The proposed aggregated multi-criteriabased approach integrates seven indicators obtained from the crossing of three elements: the seven principal lean management variables identified after a Pareto analysis of the literature review, the eight lean wastes and the four main warehousing activities. The information gathered was organised in a systematic manner thanks to a functional analysis of the WGL index. The proposed tool is strongly oriented towards its practical industrial implementation. A case study is presented, in which the tool has been successfully introduced in a French-Argentinian winery's warehouse. Findings show that the use of this tool over a period of time favours the achievement of the lean warehousing management objectives, such as waste elimination (+6%, reducing inventory and number of stock keeping units and increasing inventory accuracy) and cross-functional teams and empowerment (+12%). By analysing the results, it is possible to observe an improvement in the WGL (+11%).