The Men's 50 Breaststroke event at the 10th FINA World Aquatics Championships swam July 22 – 23, 2003 in Barcelona, Spain. Preliminary[1] and Semifinal[2] heats were on 22 July, with Prelims swum in the morning session and Semifinals in the evening session. The Final[3] swam in the evening session on 25 July.
At the start of the event, the existing World (WR) and Championship (CR) records were: