Abstract I argue in this paper for a novel analysis of case in Icelandic, with implications for case theory in general. I argue that structural case is the manifestation on the noun phrase of features which are semantically interpretable on verbal projections. Thus, Icelandic case does not encode features of noun phrase interpretation, but it is not uninterpretable either; case is properly seen as reflecting (interpretable) tense, aspect, or Aktionsart features. Accusative case in Icelandic is available when the two subevents introduced in a transitive verb phrase are temporally identified with each other, and dative case is available when the two parts are distinct. This analysis bears directly on the theory of feature checking in the Minimalist Program. Specifically, it is consistent with a restrictive theory of feature checking in which no features are strictly uninterpretable: all formal features come in interpretable-uninterpretable pairs, and feature checking is the matching of such pairs, driven by legibility conditions at Spell-Out.