The pagaré (promissory note) is still the most-used instrument in Mexico to document a loan between private parties. No bank, no notary required — a sheet of paper with correct data and a signature is enough. What almost no one knows is that a badly drafted pagaré loses force in court. If you're lending money to a relative or partner — or being asked to sign one — you need to know exactly what it must say.
What Mexican law says about a pagaré
Articles 170-174 of the Ley General de Títulos y Operaciones de Crédito define the requirements. Five elements make a pagaré valid: the word «pagaré» in the text, the unconditional promise to pay a specific sum, the beneficiary's name, the place and date of payment, and the place and date of signing plus the signer's signature.
Miss even one and the document stops being an executive pagaré. It still proves the debt, but the collection lawsuit gets harder and takes much longer.
Real pagaré example, 50,000 pesos
Here's how a well-drafted pagaré looks for a private loan: «Bueno por $50,000.00 (Fifty thousand pesos 00/100 M.N.). In Mexico City, on June 25, 2026, I owe and will unconditionally pay to the order of Juan Pérez García the amount of fifty thousand pesos 00/100 Mexican currency, value received to my full satisfaction. This amount I shall cover on December 25, 2026 in Mexico City. In case of default, late-payment interest accrues at 5% monthly on outstanding balance until full settlement. Signer: María López Hernández. Address: Av. Insurgentes Sur 1234, Col. del Valle, CDMX, CURP LOHM850612MDFPRN03. Signature: _______________.»
That's it. Fits on half a page, no formal witnesses needed (though one helps in court), no notary required.
Clauses that cannot be missing
The unconditional promise to pay. If it says «I will pay if I can afford it» or «I will pay when possible», it's no longer a pagaré. It has to be categorical.
The maturity date. Can be on a fixed date, a certain time after signing, a certain time after sight, or on demand. Fixed date is the most common for private loans.
Late-payment interest. If you don't agree on them explicitly, the supplementary law sets 6% annual — low for real risk. Reasonable for private loans is 3% to 8% monthly on outstanding balance depending on trust relationship and term.
The signer's address. Without this data, serving the debtor in a lawsuit becomes painful. Include CURP or RFC too for unambiguous identification.
Mistakes that void a pagaré
Missing autograph signature. A scanned, printed or «simple electronic» signature is invalid for a pagaré. Only direct ink on the original counts.
Different amounts in letters and numbers. If letters say fifty thousand and numbers 50,500, the law resolves in favor of the lower amount — which sometimes isn't what was agreed. Match them exactly.
Blank spaces when signing. Never sign a pagaré with empty spaces in amount, date or beneficiary fields; anyone can fill them in later with invented figures. If using a preprinted form, strike out unused spaces with a horizontal line.
Visible alterations. Any cross-out, scrape or correction fluid raises manipulation suspicion. If you erred, redo the entire pagaré. Don't correct on the original.
Do I need a notary for a pagaré?
No. The pagaré is an executive credit instrument by itself. Notarization doesn't add legal force, only public faith over date and signature. If the amount is high (say over 200,000 pesos) or the relationship is delicate, having signatures ratified before a notary adds security, but it's not required.
What to do if the pagaré isn't paid at maturity
You have three years from maturity to start executive mercantile lawsuit. The lawsuit is relatively quick (3-12 months), doesn't require re-proving the debt — the pagaré itself is proof — and allows precautionary seizure of debtor assets.
Before court, send a written demand for payment by registered mail with acknowledgment or burofax. That interrupts prescription and sometimes resolves without courts. If in CDMX, the Superior Court has accessible demand forms and small executive lawsuits are resolved in minor-amount courts with minimal fees.