INSS (Instituto Nacional de la Seguridad Social)
The INSS is the branch of the Spanish social security system responsible for managing and paying out benefits. It handles retirement pensions, disability pensions, temporary incapacity benefits (sick leave), maternity and paternity leave, orphan benefits, and widow/widower pensions. If the TGSS is the body that collects your contributions, the INSS is the body that pays you when you need benefits.
What INSS handles
The most common interactions with the INSS are: applying for your Spanish retirement pension when you reach the qualifying age, registering as a pensioner arriving from another EU country with an S1 form, claiming temporary incapacity benefits during extended sick leave, applying for permanent disability assessment, and claiming maternity or paternity benefits.
INSS versus TGSS
The distinction is simple. The TGSS (Tesorería General de la Seguridad Social) handles the money coming in: it collects contributions from employers, employees, and autónomos, and manages the NUSS registration. The INSS handles the money going out: it assesses entitlements and pays benefits. You register with the TGSS. You claim from the INSS.
When new residents encounter the INSS
Most new residents encounter the INSS when registering as a pensioner with an S1 form from their home country. The INSS processes the S1, assigns your NUSS if you do not already have one, and activates your entitlement to Spanish public healthcare. For EU citizens arriving as retirees, this is often the first substantive interaction with the social security system after empadronamiento.
