Swimming at the 2009 World Aquatics Championships – Women's 4 × 100 metre freestyle relay
The women's 4×100 m freestyle relay at the 2009 World Aquatics Championships took place on July 26, 2009 at the Foro Italico in Rome, Italy.
Records
The existing records when the event started were:| Record | Swimmer | Time | Location |
| WR |  Inge Dekker Ranomi Kromowidjojo Femke Heemskerk Marleen Veldhuis | 3:33.62 |  Eindhoven 2008 |
| CR |  Lisbeth Lenton Melanie Schlanger Shayne Reese Jodie Henry | 3:35.48 |  Melbourne 2007 |