Started as a way to lift the city's spirits after the disastrous 1906 San Francisco earthquake, it is the longest consecutively run footrace in the world.
During World War II participation sometimes slipped below 50 registrants, but the tradition carried on.
Large numbers of participants walk the route behind the runners. Some participants dress in elaborate costumes or, though not technically allowed, wear nothing at all (except footwear), thus lending a party atmosphere to the event.
The route is typically dotted with various local bands performing.
In February 2009, city officials and race sponsors announced major changes to the race regulations.
The regulations included an official ban on floats, alcohol, drunkenness and nudity.
The changes were made to assuage the concerns of San Francisco residents along the parade route, who say the race has gotten out of hand in recent years.
The news sparked outrage amongst many Bay Area residents who said the changes would destroy everything that has made the race a national treasure for most of the last century.
On February 27, 2009, city officials and race organizers announced that they were lifting many of the restrictions.