County Vendors


700 W9 FORM

Nassau County Request for Taxpayer Identification Number and Certification

Vendors are required to fill out this form in order to do business with the County. IN ORDER TO RECEIVE YOUR PAYMENTS ELECTRONICALLY Section 2 must be completed. The form must be signed and sent to:

Mail: Nassau County Comptroller’s Office
Vendor Claims Department
240 Old Country Road
Mineola, NY 11501
Fax: 516-571-2533


In order to receive payment you may either submit your own invoice/voucher* or the Nassau County Claim Voucher NIFS560. Claim vouchers should be mailed to the Nassau County department that has received the goods or services.

*Note: If you wish to use your own invoice/voucher, the ‘Claimant's Certification’ disclosure statement printed below must be copied to your form.  Your signature is required.


I hereby certify that this claim voucher is just, true, and correct; that the amount claimed is actually due and owing and has not been previously claimed; that no taxes from which the County is exempt are included; and that any amounts claimed for disbursements have actually and necessarily been made. I further certify that all items and/or services were delivered or rendered as set forth in this claim, and for all items and/or services delivered or rendered in accordance with a purchase order or contract that the prices charged are in accordance with the reference purchase order or contract. For all claims made as reimbursement for employee expenses, I further certify that the amounts set forth were actually and necessarily expended for the benefit of Nassau County, and that the monies expendedhave not been reimbursed nor do I expect to be reimbursed from any source.


Not-For-Profit Agency Financial Controls Questionnaire

This questionnaire must be completed by all not-for-profit agencies contracting with Nassau County.  The completed questionnaire should be sent to the Comptroller’s Office Field Audit unit:

Mail: Field Audit Unit Room 207
Nassau County Comptroller’s Office
240 Old Country Road
Mineola, NY  11501

(Inquiries about the questionnaire should be sent to this email address)