A denial letter is frightening, but it is not the end of your claim. Many denied California workers' comp claims are later accepted or resolved in the worker's favor. The key is to understand why it was denied and to act quickly, because appeal deadlines are strict.
Why claims get denied
- Disputed work-relatedness — the insurer claims your injury didn't happen at work or was caused by something else.
- Late reporting — you reported after the 30-day window, giving the insurer an argument.
- No medical evidence — gaps in treatment or missing documentation.
- Pre-existing condition — the insurer blames an old injury (an apportionment fight).
- Missed deadlines or paperwork errors — sometimes the denial is procedural and fixable.
Read the denial letter carefully
The letter must state the reason for the denial. That reason tells you what evidence you need — for example, a clearer doctor's report linking the injury to your job, or proof of when you reported it.
Your right to appeal: the WCAB
You challenge a denial by filing with the Workers' Compensation Appeals Board (WCAB). The first step is usually filing an Application for Adjudication of Claim, followed by a Declaration of Readiness to Proceed to request a hearing. A judge — not the insurance company — then decides disputed issues. See our hearings and appeals guide.
Watch the one-year deadline
You generally have one year from the date of injury (or last benefit/treatment) to file your claim with the WCAB. A denial does not pause this clock. Missing it can permanently bar your claim, so this is a point where many workers decide to get an attorney involved.
Medical disputes vs. legal disputes
If the fight is about treatment the insurer won't authorize, that runs through Independent Medical Review. If the fight is about whether your injury is covered at all, or how much disability you have, that's resolved through a QME/AME evaluation and, if needed, the WCAB.