California law allows lawsuits against unnamed defendants (the “John Doe” or “Doe” defendant) if the plaintiff doesn’t know the real defendant’s identity when the lawsuit is originally filed. Once the identity is discovered, the lawsuit can be amended to include the real name, and this amendment relates back to the original filing date. The question for litigators is whether the filing of the Doe amendment relates back when their ignorance of the actual name of the defendant is due to negligence or the lack of diligence. Answer: Yes. CCP 474 should be applied liberally and applies even if the plaintiff could have discovered the identity with more effort, so long as he wasn’t’ aware of the connection between the defendant and the lawsuit at the time of filing.