Swimming at the 2009 World Aquatics Championships – Women's 50 metre butterfly

The heats for the women's 50 m butterfly race at the 2009 World Championships took place in the morning and evening of 31 July, with the final in the evening session of 1 August at the Foro Italico in Rome, Italy.

Records
Prior to this competition, the existing world and competition records were as follows:

The following records were established during the competition: