Swimming at the 2009 World Aquatics Championships – Women's 4 × 100 metre medley relay

The Women's 4x100m Medley Relay at the 2009 World Aquatics Championships took place on August 1, 2009 at the Foro Italico in Rome, Italy.

* Swimmers who participated in the heats only and received medals.

The existing records when the event started were: