The two most ancient writing systems, Sumerian cuneiform and Egyptian hieroglyphs share one feature: the use of so-called “determinatives” thought to be of purely graphic nature and unpronounced. After considering the state of the art discussion of these cuneiform determinatives, the first contribution of this paper is to present a consolidated list of the alleged cuneiform determinatives, including a short discussion of the various entries, related to their semantics, estimated origin, frequency and chronological distribution. The second import of this paper is to further demonstrate that the Sumerian determinatives constitute a “noun classifier” system strikingly similar to better-studied classifier systems. This demonstration starts by establishing the particular categorization domains and functions of the Sumerian system, in order to then compare it with two classifier systems: one a noun classifier system in a contemporary Mayan language (Jakaltek), the other that of the Ancient Egyptian script, a much more complex system in its inventory, use and function but including a similar classification function. It is suggested in conclusion that a future path of research should discuss in detail how the Sumerian classifier system emerged and in what ways it forms the basis for the later evolution of classifiers in the cuneiform world, taking up both the issue of noun formation and noun classification in that script, to eventually establish Sumerian as the earliest attested language with true noun classification.