A variable stiffness catheter having two concentric coils. A first coil is fixed with relation to the body of the catheter and a second coil is able to rotate in the space between adjacent turns of the first coil. The second coil translates axially in response to being rotated. When the second coil is advanced to its distal position, the stiffness is maximized. When the second coil is retracted proximally, the stiffness of the coil is reduced.
