Manufacturing enterprises need to manage many inventory items. To effectively manage the inventory, a usual practice is to classify the inventory items into several groups and use different management strategies for the items in different groups. ABC classification has been widely used, and has evolved into various multi-criteria classification schemes. Recently, a few multi-criteria ABC classification approaches using variable weights appeared in the literature. This paper analyzes their properties and proposes an improved approach. A numerical example is included to illustrate the appropriateness of the proposed approach.