The women's 4 × 100 metres relay at the 2009 World Championships in Athletics was held at the Olympic Stadium on August 21 and August 22.
Source:[1] Prior to the competition, the following records were as follows.
No new world or championship record was set during this competition.
The first 2 of each heat (Q) plus the 2 fastest times (q) qualify.
Key: DNF = Did not finish, DNS = Did not start, NR = National record, Q = qualification by place in heat, q = qualification by overall place, SB = Seasonal best Key: SB = Seasonal best