There is provided a blind rivet (10) comprising an axially hollow tubular body (18) having a tail end face (22) at one end and a pre-formed radially enlarged flange (20) at the other end, together with a mandrel (30) having a stem (32) which extends co-axially through the body (18) and having enlarged head adjacent the tail end (22) of the body, the stem having a weakeded region immediately adjacent the head, whereby the mandrel head having an outer diameter greater than an outer diameter of said body, usually by between 4% and 9%, and which has a uniform conical shoulder (38) extending between said outer diameter of head and the stem (32), so as to exert a setting force having an axial component for compressing the rivet body axially and an angular component effecting conical deformation of the tail end radially. There is also provided a method of fastening at least two workpieces using such a blind rivet (10), including providing the blind side of the workpieces with a countersunk region to accommodate the conically deformed tail end of the body after setting, substantially flush therewith.