The women's 800 metres at the 2004 Summer Olympics as part of the athletics program were held at the Athens Olympic Stadium from August 20 to 23. The first round had split a full roster of runners into six heats with the first three gaining a direct qualification and then the next six fastest across all heats advancing to the semifinals. The top two runners in each of the three semifinal heats moved on directly to the final, and they were immediately joined by the next two fastest from any of the semifinals.