The 5K run and walk started at 9 a.m. outside the Ferry Building, where participants ran along the Embarcadero.
So far this year, the race has raised more than $200,000 for breast cancer research and treatment. The goal is $300,000.
ABC7 News' Kate Larsen emceed the event in San Francisco.
The Susan G. Komen Race for The Cure is the largest and most successful education and fundraising event for breast cancer.