The women's 400 metre individual medley competition of the swimming events at the 2019 Pan American Games was held on August 9, 2019, at the Villa Deportiva Nacional Videna cluster.

[1] Prior to this competition, the existing world and Pan American Games records were as follows: The first round was held on August 9.

[2][3][4][5] The B final was also held on August 9.

[6] The A final was also held on August 9.

[7]