Petri nets are a tool that has been booming mainly in flexible manufacturing engineering and its processes, to perform modeling, control and diagnosis of systems. This work presents a description of Petri nets with their mathematical and graphic representation to introduce the tool and facilitate its understanding, and then establish a general overview of its applications as a result of the respective bibliographic review. It also provides examples as part of the results of its application. Finally, it is concluded that it can be incorporated into various areas where complex systems or processes are used, and even as part of a teaching tool.