In a recent paper Yager (1988) introduced a special type of aggregation operators which he called OWA-operators and applied it to multicriteria decisionmaking. In our paper we give a more general definition of such operators and investigate in some detail the structural properties of them. In particular we introduce a well motivated ordering relation on weight systems which is different but compatible with Yager's degree of “orness”. Our results have immediate applications to the theory of generalized quantifiers as also discussed by Yager. Details concerning this topic will appear in a future paper.