The Arizona medical malpractice statute of limitations gives you two years to file a lawsuit, measured from the date you discovered or reasonably should have discovered that a healthcare provider’s negligence caused your injury. The rule comes from A.R.S. § 12-542, and missing the deadline almost always ends the claim, no matter how strong it is on the merits.1Arizona Legislature. Arizona Code 12-542 – Injury to Person; Injury When Death Ensues; Two Year Limitation Several exceptions can shorten, lengthen, or complicate that window, and a separate procedural rule requires an expert affidavit before your case can move forward.
The Two-Year Rule
A.R.S. § 12-542 sets a two-year statute of limitations for personal injury actions, and medical malpractice claims fall within that category. Once two years pass after the cause of action accrues without a lawsuit on file, a defendant who moves to dismiss will win. The court has no discretion to extend the deadline out of fairness, and there is no built-in grace period.1Arizona Legislature. Arizona Code 12-542 – Injury to Person; Injury When Death Ensues; Two Year Limitation
When the Two Years Actually Begins
The clock does not necessarily start on the date the mistake happened. Arizona applies the discovery rule, which starts the two-year period when you know, or reasonably should know, two things: that you were injured, and that the injury was caused by negligent medical care.
This matters when the harm is hidden or slow to appear. A misread pathology slide, a missed cancer diagnosis, or a retained surgical sponge can go undetected for months or years. In those cases, the two years runs from the date you learned about the problem, or the date a reasonably diligent patient in your position would have learned about it.1Arizona Legislature. Arizona Code 12-542 – Injury to Person; Injury When Death Ensues; Two Year Limitation
The burden of proving late discovery falls on you. If you file more than two years after the underlying medical event, you have to show a court that you could not have found out sooner through reasonable effort. Judges look at whether you followed up on symptoms, sought second opinions, and paid attention to what your providers told you. Simply not knowing is not enough if the court decides you should have.
Wrongful Death Claims
When medical negligence kills a patient, the family’s claim is also governed by the two-year limit in § 12-542, but the clock runs from the date of death rather than the date of the negligent act. That can shift the timeline substantially. If a patient received negligent treatment in 2023 but did not die from its effects until 2025, the family has until 2027 to sue, even though the original error is more than two years old.1Arizona Legislature. Arizona Code 12-542 – Injury to Person; Injury When Death Ensues; Two Year Limitation
Extra Time for Minors and Incapacitated Patients
A.R.S. § 12-502 pauses the limitations period for patients who cannot protect their own legal interests. If the injured patient was under 18 when the malpractice occurred, the two-year clock does not begin until they turn 18. In practical terms, a minor has until their 20th birthday to sue.2Arizona Legislature. Arizona Code 12-502 – Effect of Minority or Insanity
The same tolling applies to a patient who is of “unsound mind” when the cause of action accrues. Time spent in that condition does not count against the deadline, and once the disability ends the person has the full two years to file. These tolling rules stack with the discovery rule, so a minor who also could not reasonably have discovered the injury gets both protections.2Arizona Legislature. Arizona Code 12-502 – Effect of Minority or Insanity
Claims Against Public Hospitals and Employees
If your provider is a public entity or public employee, such as a county hospital or a doctor at a state-run facility, a much shorter preliminary deadline applies. A.R.S. § 12-821.01 requires a formal notice of claim within 180 days after the cause of action accrues. Miss that six-month window and the claim is permanently barred, even though the two-year statute of limitations has not yet run.3Arizona Legislature. Arizona Code 12-821.01 – Authorization of Claim Against Public Entity, Public School or Public Employee
The notice of claim is not a lawsuit. It is a written document stating facts sufficient to explain the basis for liability, a specific dollar amount for which the claim can be settled, and facts supporting that amount. You file it with the person authorized to accept service for the public entity under Arizona’s civil procedure rules.3Arizona Legislature. Arizona Code 12-821.01 – Authorization of Claim Against Public Entity, Public School or Public Employee
A few provisions cushion the requirement. Accrual runs from the point when you realize you have been harmed and know or should know the cause. Minors and incapacitated persons get 180 days from the end of the disability. And if the public entity does not respond in writing within 60 days, the claim is deemed denied and you can proceed to court.3Arizona Legislature. Arizona Code 12-821.01 – Authorization of Claim Against Public Entity, Public School or Public Employee
Claims Against VA Hospitals and Federal Facilities
Arizona has several VA medical centers and Indian Health Service facilities. If your claim involves a federal employee acting within the scope of their job at one of these locations, Arizona’s state deadlines do not apply. The Federal Tort Claims Act controls instead.
Under 28 U.S.C. § 2401(b), you must present a written administrative claim to the responsible federal agency within two years after the claim accrues. You cannot skip that step and file a lawsuit directly. If the agency denies the claim, you then have six months from the date the denial is mailed to sue in federal court. If the agency does nothing for six months, you can treat that silence as a denial and file suit.4Office of the Law Revision Counsel. 28 USC 2401 – Time for Commencing Action Against United States
One critical difference: the FTCA does not toll the deadline for minors. A child injured at a VA hospital faces the same two-year administrative deadline as an adult. Confusing the federal system with the state one is a common way to lose a viable claim, particularly because the administrative filing requirement has no exceptions.
The Expert Affidavit Trap
Filing on time is necessary but not sufficient. A.R.S. § 12-2603 requires that when you assert a medical malpractice claim, you or your attorney file a written certification stating whether expert testimony is needed to prove the provider’s standard of care or liability. In most malpractice cases, the answer is yes.
When expert testimony is required, you must serve a preliminary expert opinion affidavit along with your initial disclosures under the civil procedure rules. The affidavit must set out the expert’s qualifications, the factual basis for each claim, the specific acts or omissions that violated the standard of care, and how those acts caused your damages.5Arizona Legislature. Arizona Code 12-2603 – Preliminary Expert Opinion Affidavit
Failing to serve the affidavit when one is required leads to dismissal. The dismissal is without prejudice, so refiling is possible, but only if the statute of limitations has not run. Because finding a qualified reviewing expert, having them read the records, and drafting a proper affidavit typically takes months, this work needs to start well before the two-year deadline.5Arizona Legislature. Arizona Code 12-2603 – Preliminary Expert Opinion Affidavit
No Absolute Outer Deadline
Many states impose a statute of repose on medical malpractice claims, which is an absolute outer deadline measured from the date of the medical act itself that cannot be extended by the discovery rule, tolling, or any other doctrine. Arizona has no such repose period for medical malpractice. The discovery rule can therefore push the filing deadline well past two years from the date of treatment, provided you can show a reasonable person in your position would not have discovered the injury sooner.
Compared to states that impose a hard cutoff of six, eight, or ten years regardless of when symptoms appear, Arizona’s rule is meaningfully more forgiving for patients whose harm surfaces late.
What the Timeline Looks Like in Practice
Understanding the deadlines is one thing. Meeting them is another. Working backward from the two-year mark, several things realistically need to happen:
- Request complete medical records from every provider involved. Records requests can take weeks, and providers sometimes stall.
- Retain a qualified medical expert to review the records and form an opinion, since the § 12-2603 affidavit cannot be drafted without one. Finding the right expert and getting a thorough review often takes months.
- Identify the correct defendant. A public entity triggers the 180-day notice requirement. A federal facility triggers the FTCA administrative process. Getting the defendant’s status wrong wastes time you may not have.
- Gather evidence supporting late discovery if you are filing more than two years after the medical event, including any documents showing when and how you learned about the injury.
Waiting until the final months to start this work is the most common way people lose otherwise valid malpractice claims. The statute of limitations is a hard wall, and the preparation needed to clear it takes longer than most patients expect.