We have demonstrated a novel beam splitter for atoms. The J=1 to J=0 system in metastable helium has two independent ``dark'' states which are radiatively stable. By preparing atoms in the two ``dark'' states of the ${2}^{3}$${\mathit{S}}_{1}$ level and passing them through a sequence of partially overlapping laser beams tuned to the ${2}^{3}$${\mathit{S}}_{1\mathrm{\ensuremath{-}}}$${2}^{2}$${\mathit{P}}_{0}$ transition, we cause the atoms in one ``dark'' state to be deflected by integral multiples of 2\ensuremath{\Elzxh}k, while the atoms in the other ``dark'' state are undeflected. The excited ${2}^{3}$${\mathit{P}}_{0}$ state is not populated, so the process is unaffected by spontaneous emission. We have observed up to 90% coherent momentum transfer with 4\ensuremath{\Elzxh}k deflection. We conclude by describing how one might construct an atom interferometer based on these ``dark state'' beam splitters.