C-079 — determining the cause of sick leave (work-related or common)

C-079 (“Solicitud de determinación de la contingencia de incapacidad temporal”) is an official form of Spain’s National Social Security Institute (INSS). With it, a worker asks INSS to determine what caused their sick leave (incapacidad temporal): an accident at work, an occupational disease, a common illness or a non-work accident.

It is most often used when the sick leave was recorded as a common illness but the worker believes the injury or illness is work-related. If you ask for an accident at work or an occupational disease to be recognised, the form requires you to explain in “Alegaciones” how it happened.

• the worker; a representative (guardian, graduado social, gestor administrativo, other attorney), a de facto guardian, a curator or a judicial defender may act on their behalf;
• online — at the Sede Electrónica de la Seguridad Social (digital certificate or Cl@ve permanente);
• on paper — a signed copy by post or at an INSS centre (CAISS) by appointment;
• addressee — the INSS Provincial Directorate of your province.

• 1.1 — the worker: surnames, first name, DNI/NIE/passport, Social Security number, phones, address, e-mail;
• 1.2–1.4 — the representative, de facto guardian or curator / judicial defender, if the worker does not file personally;
• 2 — start date of the sick leave, link to earlier sick leaves, which cause you ask to be recognised; for an accident — the date, whether it was on the way to work or while teleworking, the company and job; for an occupational disease — where and as what you worked;
• 3 — statement of how it happened; 4 — two consents, place and date of signing, INSS province.

• DNI; foreigners — passport or national ID card and NIE or TIE; the representative’s ID if they file;
• proof of representation; for a de facto guardian, curator or judicial defender — the court decision or authorisation (resolución o autorización judicial);
• medical reports and sick-leave documents (parte de accidente de trabajo, medical assistance report, etc.);
• for an accident on the way to or from work — an emergency service report or police report; for telework — the telework agreement and schedule;
• if INSS asks for it — a report from the company describing your work and the circumstances on the date of the possible accident (working hours, job category).

1. Tell the chat in any language when your sick leave began and what happened — at work, on the way, or under what conditions the illness developed.
2. The assistant fills the fields in capitals, ticks the right boxes, drafts a short statement in Spanish and enters the signing date.
3. Download the PDF, sign it and submit it to INSS by post or at a CAISS; you can also file online at the Sede Electrónica.

Official INSS form C-079 cas V.9 (13.08.2026): seg-social.es — C-079. Checked 2026-10-09. This is not legal advice.