Table of Contents

W-2 E-Filing: Missouri

Nina Tchistiakova Updated by Nina Tchistiakova

Due date

January 31

E-filing threshold

Must E-file if 250 or more

Filing options

Electronic filing

Transmittal form

Form MO-W3 Located in CFS Payroll System under “W-2/1099 Information Returns”

Required file name


E-filing website  

Submitting files

Before you process a file you must complete Form MO-W3 located in CFS Payroll System under ''W-2/1099 Information Returns'' and save the form to process W-2's for Missouri. The RV record in the file contains all of the data from the MO-W3. When you process the file you will be given the option to select a saved MO-W3. Do not include the paper MO-W3 with your submission as the RV record is considered the electronic version.

· If you are a Missouri employer with an active employer withholding account, use the current Missouri Tax ID and PIN number to gain access.

· If you do not know your Missouri Tax ID or PIN number, you can contact our taxpayer assistance phone lines by telephone at 573-751-7200, by email email to, or by fax at 573-522-1722.

· You will receive a confirmation number after the file is successfully uploaded. Keep this confirmation number for your records.

Third party payroll agencies filing for Missouri clients, that do not have a Missouri Employer Withholding account and did not register with us last year, will need to send an email to to request an MO-W3 Submission Account. Please include the responsible person’s name, email address, and phone number in your request.

NOTE: If you have already registered for the EF1099 submission you do not need to register again.

When a file cannot be processed, the user will be notified by email, any reject is a reject of the entire file. The email will contain a subject of “EFW2 Rejected”, the email will include recommendations on how to correct the file. When resubmitting a file after a reject be sure to upload the entire file, as if you are submitting for the first time.

Prior year data 2017 must be submitted by paper. Corrctions are done on paper.

The file that is created can be submitted to City of Kansas City, Missouri. You may upload files via the web portal at, File name should include name of employer or the name of the payroll company/accounting firm if the file contains more than one employer. The file MUST have a .txt extension.

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