A multi-purpose closure device for the tubular stem of an inflatable balloon including two wings which are interconnected by a hinge for movement from an open to an interlocked position wherein a stem of an inflated balloon is held therebetween and a closure member mounted on one wing passes through an opening on the other and interlocks with the other wing in order to seal the stem of the inflated balloon whereby a balloon can be reliably sealed by compressing and clamping a balloon stem. The closure member may also be provided with an adhesive layer on at least one wing for attachment to other surfaces, an opening in the hinge for a string and tapered portions adjacent the hinge to hold a string.