The present invention relates to a dilator (30). The dilator includes a shaft (32), a lumen (41) and a hub (43). The shaft has at least two stiffness sections with the stiffness sections becoming less rigid as they approach a distal end of the shaft. The varying stiffness sections allow the dilator to track along the guidewire through torturous vasculature so as the dilator is advanced and the stiffness is changed, the stiffer sheath can advance smoothly through a blood vessel. The dilator may also taper at the distal tip to stretch the initial skin puncture hole larger to accommodate the dilator shaft and ease the sheath tip insertion through to the vasculature. Or the shaft may taper from where it extends beyond the sheath distal tip to the distal end so that it can reach further distal in the vasculature. The dilator may also include an atraumatic tip for easier advancement of the dilator. The dilator distal end may also include one or more radiopaque markers and a shaped distal end.