This paper provides an event-structural analysis of accusative assignment in Ukrainian and Russian impersonal predicates. Constructions in which accusative occurs in the absence of an external argument, i.e., Transitive Impersonals, are found to be necessarily dyadic and causative: one argument identifies a causing or initiating event while a second argument is associated with the verb's core meaning. The causing event is introduced by a syntactic head within the verb's extended functional projection that is responsible for accusative valuation, but is not argument-projecting (following Pylkkänen 2008). Event structure is thereby linked directly to Case, further elucidating the role of v in accusative valuation, and providing new evidence for event decompositional approaches to syntax. Additional support for this approach is adduced from a non-cognate impersonal construction in Russian.