Slicing is useful for many software engineering applications and has been widely studied for three decades, but there has been comparatively little work on slicing extended finite state machines (EFSMs). This paper introduces a set of dependence-based EFSM slicing algorithms and an accompanying tool. We demonstrate that our algorithms are suitable for dependence-based slicing. We use our tool to conduct experiments on 10 EFSMs, including benchmarks and industrial EFSMs. Ours is the first empirical study of dependence-based program slicing for EFSMs. Compared to the only previously published dependence-based algorithm, our average slice is smaller 40 percent of the time and larger only 10 percent of the time, with an average slice size of 35 percent for termination insensitive slicing.