This article shows the importance of obtaining, presenting and analyzing documentary evidence as sufficient and relevant evidence in the audit engagement. This study is supported in the conceptualization and theoretical information about the characteristics of a valid document in the audit assignment, generalities of the documents and the importance of the same as evidence of documentary evidence. Methodologically the present study is descriptive, part of a qualitative approach to be based on an information study without numerical measurement, using the analytical method. The results of the investigation confirm that the practice of documentary evidence - which is obtained through the physical or electronic inspection of the documents that support operations and transactions - generates greater confidence and credibility in the audit process as regards To the field work, because it provides the necessary elements for the audit exercise to be reliable, productive and in turn can generate added value to the organization being audited, becoming actions of improvement and guarantee for the company and the community.