What Is California Code of Civil Procedure 340.5?

Under the California medical malpractice statute of limitations, you have one year from the date you discovered the injury or three years from the date the injury occurred to file a lawsuit, and whichever deadline arrives first is the one that controls.¹ That “whichever comes first” rule, set out in Code of Civil Procedure 340.5, is what trips most people up. Children get different deadlines, a few narrow exceptions can pause the clock, and a separate statute requires you to send the provider a written notice 90 days before filing.

How the Two Clocks Run Together

Two deadlines run at the same time from the moment of the malpractice. The one-year clock starts when you discover, or reasonably should have discovered, the injury. The three-year clock starts the day the injury happened and functions as a hard outer limit.¹ You lose the right to sue the instant either one expires.

The math always resolves in favor of the earlier expiration. Discover an injury six months after a procedure, and you have six months left under the discovery clock, not a fresh full year. Discover it two years and four months in, and you have eight months left under the three-year cap, even though you’ve known about the injury for less than a year. The three-year ceiling almost always controls the back end of adult cases.

These same deadlines apply to wrongful death claims arising from medical negligence. The two-year wrongful death deadline that applies to ordinary negligence cases under CCP 335.1 does not override the shorter medical malpractice rules.¹

When Does the Discovery Clock Actually Start?

The one-year clock does not wait for a definitive diagnosis or a lawyer’s opinion. It starts when a reasonable person in your position would suspect that a health care provider’s negligence played a role in the injury. The statute’s phrase is “through the use of reasonable diligence should have discovered” the injury.¹ If warning signs appeared and you chose not to look into them, the clock was already running.

The date of injury and the date of discovery are different events, and both matter. A surgery in March might injure you on the table even though symptoms don’t appear until August. In that case, your one-year window opens in August, and the three-year cap still counts from March.

Deadlines for Children

Minors operate under a different framework. The one-year discovery rule does not apply to them at all. Every child injured by medical malpractice has three years from the date of the wrongful act to sue.¹

Children under six get extra protection. For them, the deadline is three years from the wrongful act or the child’s eighth birthday, whichever gives the family more time.¹ A child injured at age two gets until age eight because that’s longer than three years from the injury. A child injured at age five hits both deadlines at the same point, so neither rule helps more than the other.

The statute adds one tolling provision just for minors. If a parent or guardian and the defendant’s insurer or provider engaged in fraud or collusion that kept the child’s case from being filed, the deadline pauses for as long as the wrongdoing continued.² The general tolling rules for minors elsewhere in the Code of Civil Procedure do not apply to medical malpractice. CCP 340.5 is self-contained on this.

Exceptions That Pause the Three-Year Cap

The three-year outer limit is nearly absolute. The statute recognizes only three situations that extend it:

Fraud by the health care provider. If the provider made false statements related to the injury, the three-year clock pauses, but you must prove the fraud actually occurred.
Intentional concealment. If the provider deliberately hid the negligent act to prevent you from learning about it, the deadline is tolled. Simply not volunteering information is not enough. Active concealment is required.
Foreign body. If a non-therapeutic object was left inside you during a procedure, the three-year limit is tolled. This covers things like surgical sponges, clamps, or instrument fragments that serve no medical purpose after the operation.¹

Outside those three circumstances, the three-year wall holds. Mental incapacity can pause some other civil statutes under CCP 352, but its interaction with CCP 340.5 is limited, and courts rarely grant tolling on that basis in malpractice cases.³ If you believe one of these exceptions applies, you still need to move quickly, because proving the exception takes evidence.

The 90-Day Notice You Must Send Before Filing

Before filing a medical malpractice lawsuit in California, you have to send the provider a written notice of your intent to sue and then wait at least 90 days.⁴ This requirement, set out in CCP 364, is separate from the statute of limitations, and skipping it can sink an otherwise valid case.

No specific form is required, but the notice has to describe the legal basis of the claim and identify the nature of your injuries.⁴ A letter that just says “I plan to sue” won’t satisfy the statute.

There’s a built-in safety valve for people who realize they need to send the notice late. If you serve the notice within 90 days of the deadline’s expiration, the statute of limitations is automatically extended by 90 days from the date you serve the notice.⁴ Without that extension, the 90-day waiting period could force you to choose between complying with the notice rule and meeting the filing deadline. The extension only works if you actually serve the notice before the deadline expires.

Defendants whose names you don’t know when you file are exempt from the pre-suit notice requirement. If you identify them later under CCP 474’s fictitious-name procedure, the notice rule doesn’t apply to them.⁴

Who Counts as a Health Care Provider

CCP 340.5 only governs claims against health care providers, and the definition is broad. It covers anyone licensed or certified under Division 2 of the Business and Professions Code, including physicians, surgeons, nurses, dentists, optometrists, psychologists, and chiropractors, along with licensed clinics, dispensaries, health facilities, and their legal representatives.¹ The negligent act must also fall within the scope of what the provider is licensed to do. If the harm came from conduct outside the license, the claim may fall under general negligence rules with different deadlines, not CCP 340.5.

1
California Legislative Information. California Code CCP 340.5 – Professional Negligence
2
California Legislative Information. California Code of Civil Procedure 340.5
3
California Legislative Information. California Code of Civil Procedure 352
4
California Legislative Information. California Code CCP 364