This paper examines Konieczna-Twardzikowa's thesis (1993), which postulates the existence of a noun case-paradigm in Spanish drawing on the behaviour of Direct Objects marked with preposition and their co-referential clitics. The author argues that such stand is untenable. Transitivity in Spanish fluctuates. Transitivity parameters do not operare by themselves. The informative order of elements, global definiteness and referential indefiniteness intervene, together with the very structure of speech turn which affects the behaviour of clitics. The author concludes, with Jakobson, that a transposition of case categories characteristic of languages such as Polish into formal functional categories characteristic of languages such as Spanish, seems inadequate since even within case-paradigms, there is no diagrammaticality between cases and syntactic functions.