Puerarin shows promise as an anti-cancer compound, but its mechanism of action remains unclear. Here we explored whether and how it promotes ferroptosis in a colorectal cancer cell line. The level of ferroptosis and expression of autophagy proteins were compared between puerarin-treated HT-29 cells expressing normal or reduced levels of the autophagy protein ATG5 or the ferritinophagy protein nuclear receptor coactivator 4 (NCOA4). Puerarin increased lipid peroxidation and inhibited cell proliferation in a dose-dependent manner, indicating the induction of ferroptosis. These effects were partially reversed by ferrostatin-1, a scavenger of reactive oxygen species; by the iron chelator deferiprone; by repression of autophagy through administration of 3-methyladenine or knockdown of autophagy-related gene 5 (ATG5); or by repression of ferritinophagy through NCOA4 knockdown. Puerarin may induce the proliferative inhibition of colorectal cancer cells by triggering ferroptosis through a mechanism requiring NCOA4 ferritinophagy.