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

The men's 4 × 100 metre medley relay at the 2009 World Aquatics Championships took place on 2 August 2009 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: