This paper presents an energy saving approach to the problem of order picking in warehousing environment, which is directly related to the well-known Traveling Salesman Problem(TSP). While the available heuristic algorithms for the order-picking problem search for the route that minimizes the travel time, here the problem is addressed from the energy saving point of view. In a few words, the least energy-consuming route is identified in order to quantify the trade off in time and energy between the fastest route and the most energy economic one. Keeping in mind that often energy is as important as time, especially during a low-demand period, the current paper sheds some light into a two dimensional way of addressing the warehouse material handling problem, which saves time as well as energy. A very interesting finding is that a relatively small loss of service time in many cases may lead to a significant decrease of consumed energy without any additional cost. (c) 2005 Elsevier Ltd. All rights reserved.