Data Profiling in ETL, or Extract, Transform, Load, is the process of understanding the data that is being moved from one system to another. Through data profiling, companies can gain insight into the structure, content and quality of the data they are handling. This helps them make informed decisions on how best to cleanse, analyze, and move the data. With ETL data profiling, companies can also identify areas where their data may be incomplete, incorrect or inconsistent. By using this process, businesses can ensure that their data is properly handled and accurately represented in their target systems.