Selecting the positions in which products should be storage in warehouses is an important task in logistics administration, since the costs and level services of the whole supply chain can be affected for this decision. Product assignment to the available spaces in warehouses can reduce the overall distance require for material handling equipment and people to storage, reach and manipulate the stocks in the warehouse. This way, a correct assignment can produce a reduction in the cost of energy, a reduction in the number of forklifts and people as well as in the time required for such operations in the storage facilities. For that reason, it is really important the establishment of optimal storage positions, seeking better conditions of profitability and service levels in companies. This article presents a mathematical model for the allocation of products in the available storage spaces in the warehouses, which is based in the minimization of the total distance required in the warehouse’ global operation. Due to the mathematical complexity implied in solving the model, a genetic algorithm was used, which efficiently solves the problem. With the aim of validate the model and the genetic procedure for its solution, a comparison between the actual material allocation in a real company and the assignment proposal produced by the model in the same conditions was made, in which an effectively the model reduced the allocations costs. The model also shows a good stability due to the little variation in the results through several runs.