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Short answer
In New York, a resale certificate is Form ST-120, issued by the purchaser to the seller. The New York State Department of Taxation and Finance describes it as “a sales tax exemption certificate”. A lab or clinic that buys supplies to resell can give it to a supplier in place of paying sales tax on those items, but only for items bought for resale. The supplier must hold a valid, properly completed certificate within 90 days of the sale. This page is general information, not tax advice.
Definition and scope
Form ST-120 (edition 1/26, checked 2026-11-03) is titled “New York State and Local Sales and Use Tax, Resale Certificate”. The purchaser marks one box, either single-use certificate or blanket certificate, and states what business it is engaged in and what it principally sells. Temporary vendors must issue a single-use certificate.
The form is for items bought for resale. Its own warning says you may not use it to purchase items or services that are not for resale. If an item bought for resale is used or consumed by the purchaser in New York, the form says the purchaser must report and pay the unpaid tax directly to New York State. Contractors may not use ST-120 to buy materials and supplies; the form points them to Form ST-120.1 (Contractor Exempt Purchase Certificate), Form AU-297 (Direct Payment Permit), or paying sales tax at purchase.
For the broader national picture, see our guides on resale certificates for medical supply distributors and tax-exempt certificates for medical supplies, and the comparison of a resale certificate versus a seller’s permit. This page covers only the New York form.
How it is used in practice
The purchaser completes the form and signs it with name, title and date; the signer must be an owner, partner or authorized person. The certification on the form states that willfully issuing a certificate to evade tax may constitute a felony or other crime. The purchaser gives the completed certificate to the seller, who keeps it.
The seller’s side matters just as much. According to the form’s instructions to sellers, a New York registered vendor that accepts an exemption document is protected from liability for the tax if the certificate is valid, meaning it was accepted in good faith, was in the vendor’s possession within 90 days of the transaction, and is properly completed. Good faith means the seller had no knowledge that it was false or fraudulent and used reasonable ordinary due care. A certificate that is on time but incomplete is satisfactory if it is corrected within a reasonable period. A certificate received after the 90 days leaves both seller and purchaser bearing the burden of proving the sale was exempt. Sellers must keep a way of associating each invoice with the certificate on file, and must keep the certificate for at least three years after the due date of the return it relates to, or the date the return was filed, if later.
Part 1 or Part 2: which section a purchaser completes
The form has two parts, depending on whether the purchaser is a registered New York vendor. The rows below follow the wording of the form.
| Purchaser | Section | What the purchaser certifies |
|---|---|---|
| Registered New York State sales tax vendor | Part 1 | It holds a valid sales tax identification number (a temporary vendor also gives the expiry date) and is buying A. tangible personal property (other than motor fuel or diesel) for resale in its present form or as a physical component part of other property, or for use in performing taxable services where the property becomes a component or is transferred to the customer; B. a service for resale; or C. restaurant-type or heated food or drink for resale. |
| Not registered, and not required to register, as a New York vendor | Part 2 | It is registered to collect sales tax or VAT in another state or jurisdiction and gives its registration number (if none was issued, its business location and “not applicable”). It is buying D. property for resale delivered directly by the seller to the purchaser’s customer or to an unaffiliated fulfillment provider in New York, or E. property for resale that will be resold from a business located outside New York. |
The Department’s registration page (checked 2026-11-03) says every person who sells taxable tangible personal property or taxable services must register, including sellers from home, temporary vendors and those making one sale a year, and must do so before beginning business through New York Business Express. Its sales tax page lists a Registered Sales Tax Vendor Lookup tool.
Where it matters for lab and clinic supply decisions
The form does not name lab or medical items, and nothing here says any particular item is or is not exempt. What the form does show is what a supplier needs on file. A checklist derived directly from the form text:
- Part 1 or Part 2 completed, with the identification or registration number the part asks for.
- Exactly one box marked, single-use or blanket (temporary vendors: single-use only).
- The business description line filled in (what the purchaser is engaged in and principally sells).
- Signature, name, title and date of an owner, partner or authorized person.
- The certificate in the seller’s possession within 90 days of the transaction.
- A way to tie each invoice to the certificate, and retention for at least three years after the relevant return’s due date or filing date, if later.
The form states different consequences for each side:
| Side | As printed on ST-120 |
|---|---|
| Purchaser misuse | A penalty equal to 100% of the tax due, a $50 penalty for each fraudulent exemption certificate issued, possible felony prosecution, and revocation of the Certificate of Authority. |
| Seller with a valid certificate | Protected from liability for the tax if the certificate was accepted in good faith, held within 90 days and properly completed. |
| Seller with an invalid certificate | Sales are deemed taxable retail sales, and the burden of proof is on the seller. |
| Required to register but does not | Penalty of up to $500 for the first day and up to $200 for each additional day, to a maximum of $10,000. |
If you are weighing whether to buy and resell medical supplies at all, how to become a medical supply reseller covers the business side. For other states, see the California, Florida and New Jersey guides.
Common misunderstandings
- “It exempts anything the lab buys.” No. The form is limited to items bought for resale, and items used or consumed by the purchaser in New York are reported and taxed directly.
- “Contractors can use it.” No. The form excludes contractors, who use ST-120.1 or AU-297, or pay the tax at purchase.
- “A seller can collect it any time.” Protection depends on having the certificate within 90 days of the transaction.
- “Out-of-state buyers need a New York registration.” Part 2 exists for purchasers not registered and not required to register in New York, for the deliveries and resales listed as D and E.
FAQ
What is a New York resale certificate?
It is Form ST-120, a sales tax exemption certificate the purchaser gives to the seller for items bought for resale.
Single-use or blanket?
The purchaser marks one box. A temporary vendor must use single-use and may not issue a blanket certificate.
How long must the seller keep it?
At least three years after the due date of the return it relates to, or the filing date if later, according to the form.
Can a contractor use it?
No. The form directs contractors to ST-120.1, AU-297, or paying sales tax at purchase.
Sources
- New York State Department of Taxation and Finance, Form ST-120, Resale Certificate (1/26), checked 2026-11-03.
- New York State Department of Taxation and Finance, Register as a sales tax vendor, checked 2026-11-03.
- New York State Department of Taxation and Finance, Sales tax index, checked 2026-11-03.
