A multi-segment intraluminal guide wire comprising: an elongate first distal portion comprising a first metallic material; an elongate second proximal portion comprising a second metallic material that is different from the first metallic material, the distal and proximal elongate portions (104, 102; 204, 202; 304, 302; 404; 402) being joined together end to end by a solid-state weld joint ; a diameter of a weld region surrounding the weld joint being reduced relative to a diameter of the distal and proximal portions (104, 102; 204, 202; 304, 302; 404, 402) of the guide wire on either side of the weld region; and a stiffness adjusting sleeve disposed over the weld joint so that a transition profile of bending stiffness across the weld region is gradual rather than abrupt across the distal portion of the guide wire to the proximal portion of the guide wire , characterised in that the stiffness adjusting sleeve : is formed from a multifilar coil including multiple strands of helically wound wire disposed over the weld region so that a transition profile of bending stiffness across the weld region is gradual rather than abrupt across the distal portion of the guide wire to the proximal portion of the guide wire ; or includes a sleeve body in which at least one end thereof is tapered in thickness so that a transition profile of bending stiffness across the weld region is gradual rather than abrupt across the distal portion of the guide wire to the proximal portion of the guide wire . an elongate first distal portion comprising a first metallic material; an elongate second proximal portion comprising a second metallic material that is different from the first metallic material, the distal and proximal elongate portions (104, 102; 204, 202; 304, 302; 404; 402) being joined together end to end by a solid-state weld joint ; a diameter of a weld region surrounding the weld joint being reduced relative to a diameter of the distal and proximal portions (104, 102; 204, 202; 304, 302; 404, 402) of the guide wire on either side of the weld region; and a stiffness adjusting sleeve disposed over the weld joint so that a transition profile of bending stiffness across the weld region is gradual rather than abrupt across the distal portion of the guide wire to the proximal portion of the guide wire , characterised in that the stiffness adjusting sleeve : is formed from a multifilar coil including multiple strands of helically wound wire disposed over the weld region so that a transition profile of bending stiffness across the weld region is gradual rather than abrupt across the distal portion of the guide wire to the proximal portion of the guide wire ; or includes a sleeve body in which at least one end thereof is tapered in thickness so that a transition profile of bending stiffness across the weld region is gradual rather than abrupt across the distal portion of the guide wire to the proximal portion of the guide wire . is formed from a multifilar coil including multiple strands of helically wound wire disposed over the weld region so that a transition profile of bending stiffness across the weld region is gradual rather than abrupt across the distal portion of the guide wire to the proximal portion of the guide wire ; or includes a sleeve body in which at least one end thereof is tapered in thickness so that a transition profile of bending stiffness across the weld region is gradual rather than abrupt across the distal portion of the guide wire to the proximal portion of the guide wire . <EOS>