'The Deadman' made the announcement in the final episode of the critically-acclaimed 'Last Ride' documentary series.
Undertaker, real name Mark Calaway, last wrestled at WrestleMania 36 when he defeated AJ Styles in the first ever Boneyard Match.
And the 55-year-old stated it will be the 'perfect ending' to his three decade spell in the promotion.
"I believe I'm at a place now, post-Boneyard, which was a hellacious battle against one of the best in the business.
"Here you are, climbing on your motorcycle and taking off.
"There was a lot of thought and a lot of emotion, one of those being 'are you happy enough with that?'
"It was a powerful moment. You don't necessarily always get those. If there was ever a perfect ending to a career, that right there was it."
The seven-time world champion went on to state he would step back into the ring if WWE chairman Vince McMahon needed him.
But he stressed that he himself no longer desires being back in the squared circle.
"If Vince was in a pinch, would I come back? I guess time would only tell there.
"In case of emergency, break glass, you pull out The Undertaker. I would consider it.
"[But] at this point in my career, I have no desire to get back in the ring."
The Texas-native then goes on to liken himself to a cowboy who is riding away at the right moment.
"I'm at a point, it's time this cowboy really rides away.
"There's nothing left for me to conquer or accomplish.
"The game has changed. It's time for new guys to come up. The time just seems right.
"This documentary has helped me discover that and opened my eyes to the bigger picture and not judge myself as harshly these last few years.
"I can do more good outside the ring than I can inside. I'm finally at a place where I can accept that."
Taker made his debut with the WWE back at Survivor Series 1990 when he appeared as a mystery member of Ted DiBiase's Million Dollar Team.
He would go on to win a slew of championships as well as forge a legendary WrestleMania streak, which stood at 21-0 before losing to Brock Lesnar in 2014.
Do you think Undertaker is one of the greatest wrestlers ever?
Let us know in the comments below.
Featured Image Credit: WWE
- Vince McMahon Announces Retirement From WWE
- Dwayne 'The Rock' Johnson Linked With Bid To Buy WWE After Vince McMahon's Retirement
- Stephanie McMahon stunningly quits WWE after Vince McMahon returns to lead the company
- Vince McMahon Told Rivals Wanted To 'Put A Hit On Him' By WWE Legend Who Heard The Plan