During and prior to professional registration with the Engineering Council of South Africa, engineering graduates are expected to engage in advanced literacy practices which represent a high level of cognitive demand. This process is the final "gate" through which engineering graduates must pass in order to be acknowledged as professional engineers. This article attempts to define the literacy practices required at this professional registration "gate", by analysing the documents, processes and policies pertinent to the professional registration process. The result of this analysis is the identification of nine central literacy practices (divided into three reading practices, three writing practices and three critical thinking practices) that are mentioned in documents pertaining to professional engineering registration. Our estimates indicate that almost two-thirds of the ECSA Exit Level Outcomes' assessment criteria also require mastery of these literacy practices. Furthermore, these practices need to be scaffolded within engineering curricula from entry through to graduation. (Contains 4 figures and 1 note.)