According to a report by the New York Times, an 86-year-old woman, identified as Jane Doe, filed a complaint on Sept. 1 in Kern County Superior Court.
The woman is suing the estate of Cesar Chavez, the Cesar Chavez Foundation and the United Farmworkers Foundation.
The woman claims Chavez raped her in 1973 at the union's compound east of Bakersfield during a spring celebration. She also claims union leadership covered up his abuse of women for years.
The lawsuit outlines a second assault three or four years later.
The 86- year- old Jane Doe is suing under a California Assembly Bill which took effect January first of this year. The law reopens a two-year window for survivors of sexual assault to file claims that previously expired.
The New York Times first broke the story of alleged abuses back in March.
Several women, including fellow civil rights champion Dolores Huerta, came forward to say they were also abused by Chavez. He died in 1993.
The UFW and the Chavez Foundation have not responded to the latest claims.