The move would prevent cuts to someone's benefits based on race, age or gender.
Democratic Assemblyman Luis Alejo of Watsonville noted an instance where a worker's disability payment was cut in half because he is black, and those who reviewed his case said blacks were more susceptible to hypertension.
Alejo noted that protections against discrimination are common in state law. He said the bill would make it clear that any cut to disability awards would have to be justified by a pre-existing medical condition, not just "risk factors" or the likelihood of a condition.
The bill passed despite the objection of Republicans, who said it could drive up workers comp costs for businesses.
Opponents argued that there are safeguards already built into the system to prevent abuses and to flag discriminatory decisions.
The Associated Press contributed to this report.