Abstract: Combination insulated mug and beverage can holder comprises a one-piece flexible ring-shaped retainer with an annular groove that mounts on the upper rim of an insulated mug. The annular groove on the retainer has an outside lip that has a slightly inward bias and is of a slightly smaller diameter than the outside of the flared or beaded portion of the mug that it fastens to. The inner edge of the flexible retainer has a lip (or tabs) that face inward and slightly down and is of a smaller diameter than the beverage can it is designed to hold and engage when the beverage can is inserted into the mug with a fitted retainer. When the retainer is fitted to the mug's upper rim the insulated mug functions as an insulated holder of a beverage can and when the retainer is not fitted to the upper rim the mug can function as a normal drinking vessel.