Among the differences which divide the two trends of formal grammars of the 20th century, thoses dealing with word order have remained until now hardly analysed. However, the conception of word order in the first categorial grammars (from 1935 to 1959) contrasts strongly with Chomsky's transformational model (1957) and their originality in this respect requires careful examination. Indeed, Ajdukiewicz's syntax (1935), Bar-Hillel's bidirectional grammar (1953) and Lambek's associative syntactic calculus (1958, 1959) agree on handing order by having it intervene at all levels of analysis simultaneously. This paper clarifies the treatment of word order in theses three categorial grammars and compares them in order to establish at a conceptual level the significancve of their respective contributions to the formalization of order.