Mississippi payroll tax and registration guide

Why is this important?

The following information requests and registration instructions must be completed before you can use OnPay to run payroll. To maintain compliance with state payroll tax regulations, you will need to provide:

Your state Employer Identification Number and state tax IDs - You must be registered with all state and local agencies listed in this article
Tax rates - State and local tax offices determine these rates based on the type, age, and size of your business
TPA and power of attorney - Most tax offices require this before we can submit quarterly wage reports and deposits on your behalf

This information must be provided and maintained by you in order for OnPay to accurately file and deposit tax payments for your company. OnPay is not responsible for any penalties or interest that incur due to missing or incorrect company tax information.

Note: Each state has its own requirements, so if you pay employees in more than one state, you’ll find separate tax guides for each state.

Let Middesk handle your state tax registrations

Want help registering your business with state agencies? We've partnered with Middesk to make it simple and easy for you to stay compliant in your state — and every state — when hiring employees.

Register with state agencies and get the tax IDs you need within minutes
Manage all your government accounts in one place using Middesk's intuitive platform
Stay compliant as you grow by managing agency mail and notices from your Middesk dashboard
Foreign Qualify with the Secretary of State to create payroll tax accounts

Learn more about Middesk

What information OnPay needs from you

Use this checklist to make sure you’ve covered everything required to set up your account as a Mississippi employer so OnPay can accurately file and pay taxes on your behalf:

✔	To do:	What is this?
	Make sure your business is registered with the Mississippi Department of Revenue	Allows your business to file and pay taxes in Mississippi More info >
	Make sure your business is registered with the Mississippi Department of Employment Security	Allows your business to pay required unemployment insurance in Mississippi More info >
	Provide OnPay with your Mississippi Tax ID and deposit frequency	The employer identification number is issued by the Mississippi Department of Revenue More info >
	Provide OnPay with your Mississippi Letter ID	The 10-digit number (L0123456789) found at the top of any correspondence from the Department of Revenue More info >
	Provide OnPay with your Mississippi Unemployment Account Number	A 6-digit number unique to your account with the Mississippi Department of Employment Security More info >
	Provide OnPay with your Mississippi Unemployment (SUI) Rate	A tax rate you receive annually from the Mississippi Department of Employment Security More info >

What state and local taxes and filings OnPay handles for Mississippi employers

OnPay handles the filing of all state and local taxes for businesses in Mississippi, including:

Type of Tax	Form ID	Form Name	Frequency
Withholding	89-140	Annual Information Return	Annual
	89-105	Employer's Withholding Tax Return	Monthly
	State W-2	Wage and Tax Statement	Annual
Unemployment	UI-2	Employer's Quarterly Wage Report	Quarterly
Unemployment	UI-3	Quarterly Wage Report - Continuation Sheet	Quarterly
Other	New Hire Report	New Hire Report	As required

Where you can find the tax account numbers needed

If you are an existing employer who has previously run payroll in Mississippi, you likely already have the IDs and online accounts needed for OnPay to process your tax filings.

If you are a new employer in Mississippi, you will need to register your business with the Mississippi Department of Revenue and Mississippi Department of Employment Security. This must be completed for OnPay to be able to file and pay your Mississippi taxes.

Withholding Tax Account Number and Deposit Frequency

Existing Mississippi Employer:

You can find your Withholding Tax Account Number on notices received from the Mississippi Department of Revenue. If you cannot locate this number, please call the agency at 601-923-7088.

New Mississippi Employer: Register with the Mississippi Department of Revenue

Register online with the Mississippi Department of Revenue. (Click “Register for taxes”.)
You should receive your account number immediately after completing the online registration.

Mississippi Letter ID

All Mississippi Employers:

The identity validation and PIN verification letters are used by the Mississippi Department of Revenue to prevent fraud
If you cannot find one of these letters, contact the Department Of Revenue at (601) 923-7700. They're available from 8-5, Monday through Friday.
More information on ID Validation Letters

Register online Mississippi Employer Account Number and Contribution Tax Rate

Updated January 1, 2025

Existing Mississippi Employer:

You can find your Employer Account Number and Contribution Rate on the Contribution Tax Rate Notice sent by the Mississippi Department of Employment Security.
If you cannot find these numbers, please call the agency at 601-923-7700.
Rates can be up to 5.4% for SUTA, with a $14,000 wage base.

New Mississippi Employer: Register with the Mississippi Department of Employment Security

Register online with the Mississippi Department of Employment Security.
You should receive your Employer Account Number and Contribution Tax Rate immediately after completing the online registration.
New employer SUI rates begin at 1% for the first year, 1.10% for the second year, and 1.20% for the third year, after which the employer's rate can range up to 5.4%, as listed above, with a $14,000 wage base.

Paying employees in other states?

If you operate in multiple states or just have employees working from home across a state line, it's important to file the correct state forms for those workers. See what forms we file in the states where you pay employees.

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