Slicing is a technique, that has traditionally been applied to programs, for extracting the parts of a program that affect the value computed at a statement of interest. It is useful for many Software Engineering applications, including debugging, testing, reuse etc. In recent years, authors have begun to consider slicing at the model level. We consider slicing extended extended finite state machines (EFSMs). They are essentially interactive and may be non-deterministic, so standard techniques for slicing, developed for control flow graphs of programs with a functional semantics, are not immediately applicable. This talk will first give a brief survey of existing control dependence definitions for EFSMs. Then it will introduce two algorithms for dependence based slicing of EFSMs, by adapting the commitment closure approach of Danicic et al. We have implemented these algorithms in a tool and conducted experiments on thirteen EFSMs, including benchmark and industrial EFSMs. We report on our initial findings.