Since Chomsky(1981), it has beem widely assumed that structural case assignment and inherent case assignment are defined in terms of case assigners, more specifically, in terms of the categorial features of case assigners(Chomsky 1986 and 1995). It has been assumed that inherent case is assignde by a head of [+N]-feature, whereas structural case is assigned by a head of [-N]-feature. In this article, we will show that there arise theoretical and empirical problems with the definition of inherent and structural case assignment in terms of the categorial features of case assigners. We will also show that some properties of case assignees should also be taken into consideration whem we define/distinguish inherent and structural case assignment.