Social Security Numbers and the CMS 1500 Form

Field 1A of the CMS 1500 form requires a patient’s social security number. In most cases, you must attain and use the correct SSN.

Frequently Asked Question

Q: What If I Don't Have a Patient's Social Security Number for Field 1a?
If a patient does not have a social security number, enter “999999999” in Field 1a of CMS 1500. If a patient does have a social security number but does not want to give it out, do not enter “999999999” in Field 1a. You must get the patient’s SSN.


In cases like this, the DWC gives a provider no choice but to use the patient’s SSN. If necessary, explain to the patient that treatment cannot proceed without a patient SSN, because a missing SSN means that the provider cannot submit the bill to receive payment for the treatment.

Pro-Tip: It’s easy to mistype the 9s!  Just remember that there are nine of them -- one for each digit in a social security number.

Additional Information

Division of Workers’ Compensation Medical Billing and Payment Guide

DaisyBill Resources

Webinar: Overview of California Workers’ Compensation


Was this article helpful?

Search results for: