The women's 100 metres at the 2004 Summer Olympics as part of the athletics program were held at the Athens Olympic Stadium from August 20 to 21. In the first round, the first three runners from each of the eight heats, together with the eight next fastest overall runners (8×3+8=32), automatically qualified for the second round. In the second round, these thirty-two runners competed in four heats, with the first three from each heat and the four next fastest overall (4×3+4=16) advancing to the semifinals. In the semifinals, only the first four runners from each of the two heats move on to the final (2×4=8).