Tyson Fury vacated his WBO, WBA and IBO world heavyweight titles to focus on his treatment and recovery.
Fury, who stunned Wladimir Klitschko in their bout last November, recently opened up on his battle with depression and cocaine use.
The 28-year-old Brit has decided to give up his belts as he prepares to overcome his personal battles.
"I feel that it is only fair and right and for the good of boxing to keep the titles active and allow the other contenders to fight for the vacant belts that I proudly won and held as the undefeated heavyweight champion of the world when I defeated the long-standing champion Wladimir Klitschko," Fury said in a statement.
"I won the titles in the ring and I believe that they should be lost in the ring, but I'm unable to defend at this time and I have taken the hard and emotional decision to now officially vacate my treasured world titles and wish the next in-line contenders all the very best as I now enter another big challenge in my life which I know, like against Klitschko, I will conquer."
Fury's uncle and trainer Peter added: "Tyson will be back stronger from this and I will make sure, no matter what we have to deal with, Tyson not only comes back but will reclaim what's rightfully his.
"I'm very proud of my nephew's achievements."
Fury holds a 25-0 record with 18 KOs in his career.