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What is a NISS and who needs one

By Mariana Santos · 6 min read

The NISS, Numero de Identificacao da Seguranca Social, is the number that identifies you inside the Portuguese social security system. It has 11 digits. For individuals the first digit is 1, and the last digit is a check digit used to validate the number. It is issued by the Instituto da Seguranca Social, it is free, and it is issued once: one person, one number, for life.

What the NISS is used for

Your employer reports your hiring to Seguranca Social by your first day of work and records it under your NISS. Every monthly contribution is then logged against the same number. In the general scheme the worker contributes 11 percent of pay and the employer 23.75 percent. Self-employed workers file quarterly income declarations in Seguranca Social Direta and pay monthly contributions, again under the NISS. Benefits are claimed against the same record: unemployment benefit, sickness benefit, parental leave and pay, child benefit and, in time, your old age pension. You also use the NISS to request a contribution status statement and as your username for Seguranca Social Direta.

Who needs one

You need a NISS if you work in Portugal as an employee, if you are self-employed and issue recibos verdes, if you direct a Portuguese company, or if you do paid work or a paid internship as a student. Digital nomads on a D8 visa who live and work in Portugal use a NISS with proof of their foreign employer contract. Domestic workers use the same number under the general scheme.

Who does not need one

Studying alone does not require a NISS. Neither does owning property, holding a bank account or retiring in Portugal on foreign pension income with no Portuguese work. The NISS is not a residence permit and it does not by itself give anyone the right to work: your visa or residence status does that. It is also not your health number, which is assigned separately at a health facility.

The one rule that surprises people

A NISS generally requires proof of a work link. A signed contract, an opened self-employed activity with issued receipts, a company certificate or a foreign employer contract. A job promise is not enough. That single requirement explains most refusals, and it is why the document check matters more than the form itself.

Related guides

• NISS vs NIF vs Utente: the three numbers explained
• How to get a NISS as a self-employed worker (recibos verdes)
• NISS for employees: the contract catch-22 and how employers file