ABSTRACT An ontological analysis of time and of serial order is offered within the framework of a comprehensive ontology wherein the category of facts plays a crucial role. It is applied to distinguish them while various ways and contexts in which both have been mixed up in past and in present philosophy are discussed. The good reasons for that mix-up and the astonishing difficulty of keeping them apart are considered. The focus is more on the ontology of order than on the ontology of time. The latter is too wide a subject. It turns out that order has not really been grounded even in set theory. The ontology of serial order expounded is new. It is also needed for the adequate ontological analysis of relational facts.