Gates finished as the Chargers' career leader in receptions (955), receiving yards (11,841) and touchdown catches (116).
That 2004 season was the first of many great ones for Gates, who proceeded to make eight straight trips to the Pro Bowl between 2004 and 2011, including three consecutive First-Team All-Pro selections between 2004 and 2006.
Gates will be inducted into the Pro Football Hall of Fame in 2023.
"I never thought I would play this soccer game for so long or how happy I would be to play it with just one organization", he said in a statement.
And to the fans in San Diego, Los Angeles, across the country and around the world, thank you for your unwavering support all these years.
While Gates' legendary playing career is over, he did announce another key decision - he will continue working for the Chargers in a different capacity.
The eight-time Pro Bowler is done catching passes from Philip Rivers in the AFC West, but it's not the last you'll see of Antonio Gates. The Rivers to Gates connection over the years was something that many teams could only ever dream of coming from their tight end. That meant pretty much when he was one on one, throw it there.
But he soon transformed into one of the game's leading players in his position and retires as the Chargers' career leader in receptions, receiving yards, and receiving touchdowns - he became only the second tight end in history to reach 100 career touchdowns during the 2015 season. Mackey even has an award named after him given to the NCAA's best tight end each year.
On their official twitter account, the Chargers pay tribute to one of their best players ever. And, he is a lock to be a first ballot Hall of Famer. "He didn't just do one thing well, he did everything well".
Keenan Allen Reacts To Gates' Retirement.. In his third National Football League season, he racked up 89 catches, 1,101 yards, and 10 touchdowns.
"Antonio was an unselfish player who had the ability to do just about everything you can think of on a football field", Chargers coach Anthony Lynn said in a statement. But it wasn't until I had the privilege of coaching him that I saw his most important skill: leadership.