In this paper, we develop procedures for dividing rectangular warehouses into classes. We describe three types of classes and develop their corresponding traveling time models. A solution procedure involving a one-dimensional (or at most two-dimensional) search is developed. We show that the one-dimensional search procedure is very effective in solving most practical problems. Additionally, we show that most of the savings obtained by a full-turnover policy can be obtained with a relatively few classes—a result similar to the one obtained for the square AS/RS.