The 1998 Segunda División B play-offs (Playoffs de Ascenso or Promoción de Ascenso) were the final playoffs for promotion from 1997–98 Segunda División B to the 1998–99 Segunda División. The four first placed teams in each of the four Segunda División B groups played the Playoffs de Ascenso and the four last placed teams in Segunda División were relegated to Segunda División B.
The teams play a league of four teams, divided into 4 groups.The champion of each group is promoted to Segunda División.
See main article: 1997–98 Segunda División B.