Abstract: A tamper-proof bracelet is disclosed, which comprises an elongated band having at least one opening at one end, and a fastener at the other end. This fastener is in the shape of a housing having circumscribing walls, two of which are transverse to the band, a top wall and a bottom wall. At least one of the transverse walls is formed, close to the bottom wall, with a through aperture size to allow snug insertion of the one end of the band into the housing. Above the aperture and solid with the transverse wall is a locking tongue extending lengthwisely in the housing and gradualy tapering down into a thin edge, the tongue being resilient at least in the area of the thin edge and having a length sufficient to engage the opening in the one end of the band when the same is pushed into the housing through the aperture.