The winners were assured a place for the 2018–19 UEFA Europa League group stage.
The draw for the first and the second round was held on 28 July 2017 at 13:00 CEST in La Ciudad del Fútbol, RFEF headquarters, in Las Rozas, Madrid.
The draw for the Round of 32 was held on 28 September 2017, in La Ciudad del Fútbol, Las Rozas de Madrid.
Round of 32 pairings were as follows: the seven remaining teams participating in the 2016–17 Segunda División B and Tercera División faced the 2017–18 La Liga teams which qualified for European competitions.
This rule will also be applied in the Round of 16, but not for the Quarter-finals and Semi-finals, in which the order of legs will be based on the luck of the draw.