The works to testify are understood as assurance contracts that are not audits or review of financial information. The objective of this manuscript is to analyze the factors associated in the works to testify against other audit assignments. The type of research is a descriptive and documentary study since it seeks to relate the characteristics between these two types of insurance contracts, based on the collection of different sources of information. The results show that there are more similar factors, such as risks, stages and procedures, these are regulated in a general way in the rules to testify but are more specific in the auditing standards. It was concluded that a job to testify is the first step that must be followed prior to the performance of an audit, since it complements and allows a better regulatory verification.