The petition, filed Wednesday in U.S. Bankruptcy Court in Riverside, included the council-passed July 26 resolution authorizing the action, the Los Angeles Times reported.
San Bernardino declared more than $1 billion in liabilities and $1 billion in assets.
"There will be no immediate service reductions or changes in service to the community as a result of the filing," city officials said in a statement.
Last week, interim City Manager Andrea Travis-Miller told council members they must cut $45.8 million -- roughly 30 percent -- from the budget so the city could remain solvent in the current fiscal year. Developing an austerity plan will be required in the Chapter 9 municipal bankruptcy process.
The cuts, expected to begin this month, are expected to lead to compensation cuts or widespread layoffs, and the city's police and fire departments won't be exempt, the Times said.
San Bernardino is the third California city to seek bankruptcy protection this year, joining Stockton and Mammoth Lakes.