Among the six arrested were two members of the Hells Angels motorcycle club in Oakland, according to the sheriff's office.
The investigation began last month when sheriff's deputies smelled what they suspected to be marijuana coming from a building in the 1100 block of Fifth Avenue in Oakland, the sheriff's office reported.
An investigation by the Alameda County Narcotics Task Force led to the service of a search warrant at that building as well as a residence in the 2200 block of San Antonio Avenue in Alameda at about 7 a.m. today.
Officers recovered 58 marijuana plants as well as a "substantial sum of cash."
The sheriff's office did not immediately release suspect names or descriptions, but said both men and women were arrested.
In addition to the sheriff's office and narcotics task force, Oakland and Alameda police officers and Drug Enforcement Administration agents assisted in serving the warrants.