The goal is to present the main free and open access search engines such as PATENTSCOPE and Google Patents. It also seeks to verify the information retrieval system, which seeks to transform the user's information needs into a list or collection of documents whose content satisfies that need. We present the comparison of both verifying each one independently and then, a summary table. Finally, it is concluded that the constant search for inventions can make the difference between the positions of competences between global companies; It is for this reason that patents prove to be a source of reliable information on the subjects of interest of the people or companies. Pantestscope and Google Patents allows you to download as much data as a table for future analysis of the information. Keywords: Information retrieval, Patents, Patentscope, Google Patents, Web