Washo, a Native American isolate, displays negative concord morphology in the context of negation. Negative concord in Washo comes in the form of the morpheme -Na, which may be suffixed onto optionally many sentential elements in a single clause. Given the apparent lack of semantic contribution by this morpheme, I argue - building on accounts along the lines of Zeijlstra (2004) - that negative concord in Washo is best treated as the result of multiple agreement between an interpretable Neg feature high in the clause and optionally many uninterpretable Neg features present on the items it c-commands. Importantly, the Washo data shed light on an unexplored system of negative concord and the possible range of agreement phenomena that are sensitive to negation.