This paper discusses the transferability of skills between two forms of interpreting: consecutive and simultaneous. The research is informed by studies of expertise, and task analysis in particular. The authors use hierachical task analysis as an analytical tool to break down the processes of CI and SI into sub-tasks as the basis for the comparison of skills and for exploring transferability. In the course of these analyses, the paper also calls into question the standard training sequence of starting from CI and progressing to SI. The research is a non-empirical investigation, which aims to lay the theoretical foundation for future studies in the field.