The Men's 100 metre breaststroke SB12 swimming event at the 2004 Summer Paralympics was competed on 20 September.

[1] It was won by Dmytro Aleksyeyev, representing Ukraine.

[2] 20 Sept. 2004, morning session 20 Sept. 2004, morning session 20 Sept. 2004, morning session 20 Sept. 2004, evening session