Transabdominal preperitoneal patch plasty (TAPP) is the most frequently used surgical technique for repair of an inguinal hernia in German hospitals (Federal Statistical Office, Wiesbaden). Since its initial description in 1992 by Arregui the technique has been further developed and completely standardized, so that TAPP is now suitable as an operation performed by trainee surgeons despite the complex technique. The individual operation stages have been described by many experts mainly based on their own experiences, training with other experts, participation in meetings with live or video demonstrations and reports in the literature. A scientific explanation for the individual operation steps, i.e. why a certain technique is given preference in comparison to other techniques, is not usually communicated. In this article for the first time not only the operation steps of TAPP are described in detail but also the scientific reasons (evidence) are given.