About the document
- Who files:
- A recipient of an INSS short-term benefit (or their representative) whose details have changed
- Where to submit:
- Sede electrónica, ordinary post or an INSS centre (CAISS) by appointment
- Authority:
- Instituto Nacional de la Seguridad Social (INSS)
- Country:
- Spain
- Category:
- Social Security and pensions
- How to fill:
- Chat in any language → original form → PDF
- Price:
- form free · chat €5 per document
- Last updated:
- Official source:
- https://www.seg-social.es/descarga/es/Solicitudvariacionesdatos
What this document is
C-178 (“Comunicación de variaciones de datos para prestaciones a corto plazo”) is the official form of Spain’s National Social Security Institute (INSS). Recipients of a short-term benefit use it to report that their details have changed.
It covers temporary incapacity (sick leave), birth and childcare, risk during pregnancy and breastfeeding, infant care, care of a child with cancer or another serious illness, school insurance and one-off family benefits.
Who files it and where
- the benefit holder, their legal representative (parent, guardian, curator) or a voluntary representative;
- online at the Social Security e-office (Sede electrónica) — service “Presentación de otros escritos, solicitudes y comunicaciones (INSS)”;
- by ordinary post — a signed copy;
- in person at an INSS centre (CAISS) by appointment: 91 541 25 30 / 901 10 65 70 or inss.seg-social.es/cita.
What the form asks
- page 1 — which benefit, whether you report yourself or through a representative, and what is changing;
- 1.1 — holder: surnames, name, date of birth, sex, DNI/NIE/passport, Social Security number, nationality; 1.2 and 1.3 — representatives;
- 2 — NIE/TIE replaced by a DNI, new mobile, new e-mail; 3 — new home address and/or a separate address for notifications;
- 4 — new account (Spanish IBAN or foreign bank details); 5 — other change, two consents, place and date of signing, INSS province.
What to bring
- the holder’s DNI, passport, NIE or TIE and, if a representative files, their document too (CIF/NIF for an organisation);
- a legal representative — the court decision; a parent — the family book (libro de familia);
- a voluntary representative — proof of representation;
- for an “other change” — documents proving it.
How to fill it in with FoxDocs
- Tell the chat in any language which benefit you receive and what has changed.
- The assistant fills in only the relevant sections in capitals, splits the IBAN into its boxes and adds the signing date.
- Download the PDF, sign it and file it with the INSS in one of the three ways.
Source
Official INSS form C-178 cas V.2: seg-social.es — C-178. Checked 2026-10-09. This is not legal advice.