Delays in the time of preparation of orders in a warehouse of materials and construction tools affect delivery times, which affects the level of service and consequently the loss of customers. This, due to the waste in the existing system such as the lack of planning of the process inputs, inefficient procedures, lack of organization and total cleaning. Therefore, this document proposes the application of a Lean Model of picking based on Heijunka, Kanban, 5S and JIT techniques, to eliminate waste (time, movement and inventory). After proposing the improvements, support was made in a stochastic tool to validate the changes with respect to the current situation. Consequently, significant improvements were observed, particularly in the collector's load, reducing its load by 56.29%, eliminating the waiting times for requirements and increasing the orders served. This leads to the improvement of the productivity of the picking operation at 47.07%, resulting in timely deliveries.