This invention provides a device for closing a flexible container which comprises a body portion having first and second opposed gripping arms extending therefrom. The arms are each adapted to be folded about a fold line relative to the body portion so that the arms, with the body, are capable of at least partially encircling the flexible container for closure thereof. Each of the arms has at least one gripping and engaging means extending inwardly therefrom, and the body has a first gripping and engaging means adapted to fixedly engage the flexible container in one direction and a second gripping and engaging means adapted to fixedly engage the flexible container in a second opposed direction. Means are provided in at least one of the body or arm members for passage of a tie member operatively associated therewith. The device provides a tamperproof closure for a flexible container when used in combination with a tie and deformable sealing element.