Abstract: A urological guidewire includes a core formed of a first metallic material and extending toward an end of the guidewire. A coil having a plurality of convolutions is disposed around the core at the end of the guidewire, the coil being formed of a second metallic material different than the first metallic material. A mechanical interlock is formed to inhibit separation of the different materials forming the coil and the core. The mechanical interlock may include an enlargement at the end of the core and a bonding material fixing the enlargement to the coil. The convolutions may include a penultimate convolution with a first radius of curvature and an ultimate convolution having a second, shorter radius of curvature to form a bridge. In this case, portions of the core can be bent back on themselves and directed over or around the bridge to form the mechanical interlock.