NUSS in Spain: Why You Need Your Social Security Number Before Your First Day

What the NUSS is and what it is not

The NUSS is a unique personal number assigned by the TGSS (Tesorería General de la Seguridad Social) that identifies you within the Spanish social security system. It is a 12 digit number that stays with you for life, regardless of how many jobs you change, whether you switch from employment to self employment, whether you leave Spain and return, or whether you stop working entirely. Once assigned, it never changes.

The NUSS is not the same as your NIE. This confusion is widespread, and it causes problems. Your NIE (Número de Identificación de Extranjero) is your fiscal identification number. It is used for taxes, contracts, bank accounts, and all interactions with the Agencia Tributaria. Your NUSS is used for social security: healthcare, pensions, sick leave, maternity, and all interactions with the TGSS and INSS. They are different numbers issued by different institutions for different purposes. You need both to function in Spain, and they do not replace each other.

Think of it this way: your NIE tells Spain who you are for tax purposes. Your NUSS tells Spain who you are for social protection purposes. A Spanish citizen has a DNI number and a NUSS number. As a foreigner, you have an NIE number and a NUSS number. Same logic, same separation.

Why you need it before your first day of work

Your employer cannot complete your alta (social security registration) at the TGSS without your NUSS. If you already have one from a previous period of work or registration in Spain, the employer uses your existing number. If you have never been registered with the Seguridad Social, a new NUSS needs to be created.

Here is where timing matters. Your employer can request a NUSS on your behalf as part of the alta process, but this adds time and complexity to what should be a straightforward registration. If the employer has your NUSS ready, the alta takes minutes. If they need to request a new NUSS first, the process can take a few extra days, during which you are technically not yet registered with the Seguridad Social. That means no healthcare coverage and no contribution tracking for those days.

The practical advice: request your NUSS yourself before you start working. It is free, it is quick, and it removes a dependency from your employer's workflow. You show up on day one with your NIE and your NUSS, and the alta is processed immediately.

How to get your NUSS

There are two ways to get a NUSS: online through Import@ss (the TGSS digital portal) or in person at a TGSS office.

Online via Import@ss

If you have a Certificado Digital, you can request a NUSS through the Import@ss portal (importss.seg social.es). The process is called "Asignación de Número de Seguridad Social" and is available under the section for citizens (ciudadanos). You enter your personal data (name, NIE, date of birth, nationality, address in Spain) and submit the request. The NUSS is typically assigned within 24 to 48 hours. You can then download the assignment document from the portal.

This is the fastest and most convenient route. It does not require an appointment, does not require visiting an office, and gives you a digital record of your NUSS assignment. The only prerequisite is having a Certificado Digital, which is why we always recommend getting the digital certificate as one of your first steps in Spain.

In person at a TGSS office

If you do not have a Certificado Digital, you can request your NUSS in person at any TGSS office. You need a cita previa (booked online or by phone), your NIE or TIE (original plus copy), and a completed TA.1 form (Solicitud de Afiliación a la Seguridad Social / Asignación de Número de la Seguridad Social). The TA.1 form is available online on the Seguridad Social website. The officer processes your request and assigns the NUSS, usually on the spot.

In both cases, you do not need to be employed to get a NUSS. You do not need a job offer. You do not need to be registered as autónomo. You simply need to be a foreign resident with a valid NIE or TIE. The NUSS is an identification number, not an employment registration.

Where the NUSS appears in your daily life

Once you have your NUSS, it appears on several documents that you will interact with regularly. Your Tarjeta Sanitaria (health card) displays your NUSS and is the card you show at every GP visit, specialist appointment, and pharmacy prescription pickup. Your Informe de Vida Laboral (working life report), which tracks your entire contribution history in Spain, is organised around your NUSS. Any correspondence from the INSS (pension assessments, benefit notifications, sick leave confirmations) references your NUSS. Your payslip (nómina) may include your NUSS alongside your NIE.

Keep your NUSS written down and stored safely. Unlike the NIE, which you will use constantly and memorise quickly, the NUSS tends to be forgotten between interactions with the Seguridad Social. When you need it (changing jobs, applying for benefits, registering at a new Centro de Salud after moving), not knowing your number means an extra trip to the TGSS or an Import@ss lookup.

NUSS for autónomos

If you are registering as autónomo, the NUSS is assigned as part of your TGSS alta under the RETA scheme. You do not need to request it separately. The process is: first, register with Hacienda via Modelo 036 (your tax registration). Second, register with the TGSS for RETA (your social security registration). The TGSS assigns your NUSS during the second step if you do not already have one. If you do already have a NUSS from a previous period, the TGSS uses your existing number.

That said, if you plan to become autónomo and want to have your NUSS ready before you start the TGSS registration, you can still request it in advance through Import@ss or in person. Having it ready simplifies the RETA registration process.

NUSS for pensioners and non working residents

If you are a pensioner registering your S1 form at the INSS, the INSS assigns your NUSS as part of the S1 registration process. You do not need to go to the TGSS separately. The INSS and the TGSS share the same database; the NUSS is the same number regardless of which institution assigns it.

If you are a non working resident applying for the Convenio Especial, the INSS assigns your NUSS when they process your Convenio Especial application. Again, no separate NUSS request is needed.

The only scenario where you need to proactively request a NUSS yourself is when you are about to start working (employed or self employed) and want to have the number ready before your employer or your own TGSS registration needs it.

What happens if your employer does not have your NUSS

If you show up for your first day of work without a NUSS and your employer has not requested one, the alta cannot be completed. Your employer can request the NUSS as part of the registration process, but this creates a delay. During that delay, you are technically working without social security coverage. If you have an accident on day one, you are not covered for workplace injury benefits. If you fall ill, you are not entitled to sick leave pay through the Seguridad Social.

Most employers in Spain are familiar with the process and will either request the NUSS for you or ask you to bring it. But not all employers are equally diligent, particularly smaller companies or those hiring foreign workers for the first time. Taking the initiative to get your NUSS before you start protects you regardless of how organised your employer is.

Can you have more than one NUSS

No. One person, one NUSS, for life. If you think you might have been assigned a NUSS during a previous stay in Spain (even if you worked briefly, or registered at a Centro de Salud years ago, or applied for the Convenio Especial), you already have one. Do not request a new one; it will create a duplicate in the system that needs to be merged later, which is an administrative headache. If you are unsure whether you already have a NUSS, check through Import@ss with your Certificado Digital, or ask at a TGSS office. They can look it up with your NIE.

The NUSS and your Tarjeta Sanitaria

The link between the NUSS and the Tarjeta Sanitaria is direct. You cannot get a Tarjeta Sanitaria without a NUSS. The health card is issued by your local Centro de Salud, but the underlying registration in the Seguridad Social (which is what the NUSS represents) must be active first. The sequence is: get your NUSS (through employment alta, autónomo registration, S1 registration, or Convenio Especial), then go to the Centro de Salud with your NUSS, NIE or TIE, and empadronamiento to get the Tarjeta Sanitaria.

If you move to a different address within Spain, your NUSS does not change, but you need to register at a new Centro de Salud. Your Tarjeta Sanitaria is updated (or reissued) with your new assigned GP. The NUSS remains constant; the Centro de Salud assignment changes based on your empadronamiento.