In the new Public Policy Institute of California poll released Thursday, 46 percent of voters said they were in favor of legalization, the Los Angeles Times reported.
A ballot measure to legalize marijuana was rejected by state voters last year, although there is talk of another initiative, the newspaper said.
In the new poll, the San Francisco area was the only part of California favoring legalization, while most respondents in Southern California opposed it.
A similar split found liberals and Democrats more likely to be in favor of legalization than Republicans and conservatives, the poll showed.
The poll surveyed 2,002 adult California residents on landlines and cellphones Sept. 6-13.