CA SB 503
California Senate Bill 503 - Health Care Services: Artificial Intelligence (Clinical Decision Support Systems)
Requires developers and deployers of AI clinical decision support systems used by health facilities, clinics and physician practices to make reasonable efforts to identify systems with a known or reasonably foreseeable risk of biased impacts on people with protected characteristics. Developers must mitigate those risks and give deployers an intended-use and risk statement plus documentation on training data, evaluation and data governance; deployers must regularly monitor the systems and mitigate.
Jurisdiction
California
Enacted
Sep 30, 2026
Effective
Jan 1, 2027
Enforcement
None specified in the act
Approved by Governor Newsom and chaptered by the Secretary of State on September 30, 2026 as Chapter 857, Statutes of 2026. Adds Chapter 25.3 (commencing with Section 22758) to Division 8 of the Business and Professions Code. A 2025 bill held on the Assembly inactive file from September 10, 2025 until August 12, 2026; passed the Assembly 70-1 on August 24, 2026; the Senate concurred in Assembly amendments 39-0 on August 25, 2026; enrolled and presented to the Governor on August 30, 2026. No urgency clause, so the act takes effect January 1, 2027 under Article IV, Section 8(c) of the California Constitution.
California Legislative Information: SB 503, Chapter 857, Statutes of 2026 (chaptered text)Why It Matters
Places bias-identification and documentation duties on developers of clinical decision support AI and monitoring duties on the clinical settings that deploy it. A clinical decision support system is defined as AI that aids decisions on timing of care, diagnosis or treatment, which excludes scheduling, reminders, patient education and payment tools.
Recent Developments
Signed September 30, 2026 together with AB 1979 (Chapter 854), which bars health facilities from using AI to independently perform licensed clinical functions and brings health care chatbots under the Confidentiality of Medical Information Act.
At a Glance
Applies to
Harms addressed
Requires
Who Must Comply
- Developers of AI clinical decision support systems used in California health programs or activities
- Health facilities, clinics, physician offices and offices of group practices that use clinical decision support systems
Obligations fall on:
Safety Provisions
- Developers and deployers must make reasonable efforts to identify clinical decision support systems with known or reasonably foreseeable risk of biased impacts in health programs or activities
- Developers must make reasonable efforts to mitigate those risks
- Developers must give deployers a statement of intended uses and foreseeable risks, and documentation on training data and its demographic representativeness, performance and bias evaluation, data governance, intended benefits, known risks and mitigation, and recommended use and monitoring
- Documentation is due on request or at initial sale, whichever is earlier, and on material updates; developers may rely on recognized industry standards or regular algorithmic impact assessments
- Deployers must regularly monitor identified systems and take reasonable and proportionate steps to mitigate the risk of biased impacts
- Compliance is not a defense to a claim of unlawful discrimination
Exemptions
Administrative and patient-education tools
Systems that provide appointment management, reminders, patient education and previsit materials, or payment processing are outside the definition of clinical decision support system where their independent performance does not require a professional license
- • Appointment, reminder, education or payment function
- • No licensed function performed independently
Internal developer-deployers
A deployer that develops a system for its own internal use need not generate developer documentation if equivalent information is readily available to it
- • Developed and deployed for internal use
- • Equivalent documentation readily available
Compliance & Enforcement
Key Dates
Jan 1, 2027
Bias identification, mitigation, documentation and monitoring duties for clinical decision support systems take effect
Penalties
The act specifies no penalty or enforcement mechanism of its own. Section 22758(d) states that it supplements other state law on artificial intelligence and automated decision systems and that compliance cannot be used as a defense to a claim of unlawful discrimination.
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California
Focus Areas
Cite This
APA
California. (2026). California Senate Bill 503 - Health Care Services: Artificial Intelligence (Clinical Decision Support Systems).
Related Regulations
CA SB 947
Adds Labor Code Part 5.5.5 on employers' use of automated decision systems (ADS). Bars using an ADS to violate labor or civil rights law, to infer an employee's protected status, or to predict and act against workers exercising legal rights; bars relying solely on an ADS for disciplinary or termination decisions and requires human corroboration where an ADS output is the primary basis; and requires a written post-use notice and, on request, a description of the employee's data used. Operative July 1, 2027.
CA AB 1979
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MD HB 895
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Last updated October 4, 2026. Verify against primary sources before relying on this information.