Companies seek to have an always efficient and adequate operation, both externally and internally, the latter being the most important because all the processes carried out within the organization have an impact on its profitability, for them there are various tools that provide adequate control of all the processes carried out within it. But this does not mean that they are free of errors, since these occur frequently within companies due to various factors in which most of the human factor is involved, so it is important to detect them to avoid irregularities in the various processes that are carried out that is why there is the internal audit this is responsible for examining, verify and ensure that everything is done correctly in accordance with the procedures already established as well as the respective rules. This study will address the effectiveness of the application of this audit in companies to detect errors within it. It will be carried out through two methodologies in conjunction with the descriptive and the documentary to reach the objective of the research.