REG 124 is used for this job: Used in assigned identification-number situations when California requires a formal assigned-number process. The practical risk is not the form name; it is using the form without the right signer, source version, or supporting packet.
Use the official version before you fill anything out
The safest way to handle REG 124 is to open the agency source first, then fill the form only after you know who signs it and what documents must sit behind it.
Applicant and official personnel as required by the transaction.
Submit through the official DMV process for assigned or replaced identification number issues.
Who fills it out
The applicant completes the applicant portions; DMV/CHP involvement may be required depending on why an assigned number is needed.
Who signs it
Applicant and official personnel as required by the transaction.
Where it is submitted
Submit through the official DMV process for assigned or replaced identification number issues.
Fill it in this order
- 1
Open the official REG 124 source and confirm it matches the transaction you are actually doing.
- 2
Fill vehicle identifiers exactly from the title, registration, VIN plate/label, or agency record. Do not "clean up" spelling or numbers from memory.
- 3
Fill owner, buyer, seller, lienholder, and applicant names so they match the supporting documents.
- 4
Stop before signatures and confirm who is allowed to sign: Applicant and official personnel as required by the transaction.
- 5
Submit it only with the packet described by the office or official source: Submit through the official DMV process for assigned or replaced identification number issues.
The form is only useful if the packet supports it
Think of REG 124 as one page in a file, not the file itself. Before you sign, make sure the names, VIN, odometer, title evidence, lien status, and transaction type match the rest of the documents.
Use the exact source or PDF the office pointed to, then ask which supporting documents must travel with it.
Ask which official source they used and which signer authority they are relying on.
Verify the current version on an official agency site before you print or sign.
Common mistakes
- Using it for an ordinary VIN verification.
- Skipping the inspection or official referral step.
- Assuming a private verifier can resolve assigned-number cases.
Five-minute audit before submitting REG 124
Every owner, buyer, seller, applicant, and lienholder name should match the title or supporting document.
One wrong character can make the whole packet look like the wrong vehicle.
If the form or title transaction asks for odometer information, leave no ambiguity.
Ask whether the signer is accepted by California DMV for this exact transaction.
Keep title, bill of sale, inspection, lien, ID, and agency notice documents together.
Next step by situation
Use the official PDF or agency page linked below and complete only the sections that match your transaction.
Check the official source before signing and ask why this form is required.
Ask which field, signer, or supporting document caused the rejection, then match that answer to the source.
If REG 124 is rejected
Try not to leave with a general answer like "the form is wrong." You need the reject reason precise enough to fix the next version.
Was the problem the form version, a blank field, the wrong signer, a VIN/name mismatch, missing title evidence, missing lien release, odometer information, or a different California process?
Once you know that answer, do not patch the form casually. Some agencies allow corrections; others need a clean new form, a new verification, or a different official signer.