This paper aimed to optimize the cashier service macroprocess in a supermarket located in the Alto Paranaiba. Decision-making tools were applied, such as brainstorming, process mapping, Ishikawa diagram and PDCA cycle. The simulation type was based on the M/M/1 model, in the context of Queuing Theory. Thus, factors such as customer satisfaction and increased productivity were sought through systematic control and continuous improvement of the cashiers' service macroprocess. Finally, the alignment carried out between the PDCA cycle and the Routine Management brought an effective contribution, represented by the standardization of the macroprocess, by the construction of Standard Operating Procedures (SOPs).