The announced 9,860 registered participants are dressed in rags and ghoulish makeup to look bloody and decaying.
Organizer Pablo Guisa says the fifth annual Mexico City event is meant to celebrate diversity and human rights. The participants also collected donations for a local food bank.
Cities around the world hold zombie walks, and Guinness World Records currently recognizes Asbury Park, New Jersey, as the record holder, with 4,093 participants on Oct. 30, 2010.
A group in Brisbane, Australia, has applied for the record, claiming it massed 8,000 "zombies" last month.