How long does an employee have to inform his employer of his illness?

Employees who are ill must notify their employer or a representative of the employer directly on the first day of absence from work.

They may provide this information personally or through a third party (e.g. spouse, family member, friend, etc.). The information can be given orally (e.g. by telephone) or in writing (e.g. by fax).

In the event of a dispute, employees must be able to prove that they informed their employer of the absence due to illness.

How long do employees have to submit a medical certificate to the employer?

Employees must submit a medical certificate to their employer attesting to their incapacity to work on the third day of absence, at the latest. An employee must be able to prove that the employer received the certificate before the 3 days have elapsed.

What happens if the illness is prolonged?

The two requirements to provide notice (described in the previous question) are also to be applied in case of prolonged illness.

What are employees’ obligations towards the CNS?

In all cases where a medical certificate of incapacity for work is required, insured persons declare this status and indicate to the National Health Fund (CNS) any location where they are staying if different from their usual address. 

To declare incapacity for work, employees use only forms issued by a doctor. Medical certificates issued by doctors based abroad have the same evidential value as those issued by doctors in the Grand Duchy of Luxembourg. However, if they are not drawn up in one of Luxembourg’s official administrative languages (German, French or Luxembourgish), they must be accompanied by a translation. 

This form consists of three parts (for certificates issued in the Grand Duchy of Luxembourg. For certificates issued with only one copy, it is employees’ responsibility to make copies) and must include the following data: 

• the Luxembourg registration number of the person concerned
• the start and end dates of the incapacity for work
• the date on which incapacity for work was declared
• a disease code (optional).

Employees send the first part of the form – i.e. the original – no later than the end of the third day of incapacity for work (postmark is proof of this), to the following address: 

CAISSE NATIONALE DE SANTÉ
Indemnités pécuniaires
L-2980 LUXEMBOURG

The certificate of incapacity for work can be send by email, instead of by post: cit.cns@secu.lu

Note: You must indicate your 13-digit Luxembourg national identification number in the subject line of the e-mail and send the document in PDF format. 

Sending it by e-mail is enough, no need to send it by post.

If the incapacity to work extends beyond the period initially set, the form must be sent to the CNS before the end of the second working day following the one initially set for resumption of work.

If the last day of this period is a Saturday, Sunday or public holiday, the period is extended to the next working day.

(Last updated on 28.02.2024)