The women's 4 × 400 metres relay at the 2009 World Championships in Athletics was held at the Olympic Stadium on August 22 and August 23.
* Runners who participated in the heats only and received medals.
No new world or championship record was set during this competition.
Qualification: First 3 of each heat (Q) plus the 2 fastest times (q) advance to the final.
Key: DQ = Disqualified, Q = qualification by place in heat, q = qualification by overall place, SB = Seasonal best Key: SB = Seasonal best, WL = World leading (in a given season)