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

The heats for the women's 50 m backstroke race at the 2009 World Championships took place in the morning and evening of 29 July, with the final in the evening session of 30 July 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:

* Split from the women's 100 m backstroke