Abstract: An adjustable looseleaf binder is provided for the accumulation of sheets of hole punched paper and the like. This binder has an elongated base plate to which are attached one end of a plurality of flexible binding posts. The second ends of the binding posts are releasably held in the base plate by various clamping mechanisms thereby providing an adjustable loop of any desired size. This loop threads through the hole, or selected holes, of material to be held in the binder. A foldable sheet provides for the top, edge and bottom cover of the binder. This sheet has prescored lines therein to permit folding to achieve the desired dimensions of the binder and holes to accept the binding posts. As the contents of the binder are changed, the cover may be folded at other prescored lines to accommodate this change. The components of the binder may be readily shipped in a compact manner and assembled by the user to achieve a binder of desired size.