Sick leave in Luxembourg: certificate, deadlines, who pays you and protection
Skimming?
We've prepared the shortcut for you.
Your to-do, in 4 steps
Practical guide · trigger.lu
Sick leave in Luxembourg: certificate, deadlines, who pays you and protection
- When
- the same day, as early as possible
- How
- verbally, email, text, you or someone close to you
Details
Your employer can require a medical certificate from the first day of absence. Check your contract or the internal rules.
- Deadline
- certificate issued by the 3rd day at the latest
- Backdating
- 2 days, if you see a doctor by the 3rd day at the latest
- Parts
- 1 for the CNS, 2 for the employer, 3 for you
Details
You fall ill on Monday and see a doctor on Wednesday: your doctor can cover you from Monday. You see a doctor on Thursday: the CNS only counts your sick leave from Thursday.
- Deadline
- in their hands by the 3rd day at the latest
- Example
- ill on Tuesday, certificate with them on Thursday
- Online
- via MyGuichet.lu if they have a business space
Details
If you're abroad or the post risks being too slow, use another method (hand delivery, electronic sending).
- 2 working days or less
- nothing to send
- More than 2 working days
- before the end of the 3rd working day
- Online
- CNS form, certificate as a PDF
- Post
- CNS, Indemnités pécuniaires, L-2980 Luxembourg
Details
By post, the postmark is proof and no stamp is needed from Luxembourg. If you send it online, don't also send it by post. Write your 13-digit identification number on everything you send.
This is for you if
You're an employee in Luxembourg, resident or cross-border worker, and you can't work because of illness or an accident.
You have a medical certificate in hand and don't know who to send it to, or by when.
Your sick leave has been extended and you're wondering what to do again.
You're wondering who pays your salary during sick leave.
your child is ill: that's leave for family reasons, with its own rules. And if your sick leave has lasted several months, our guide incapacity for work goes further. Are you a civil servant or State employee? You inform your head of administration before your start time, you only owe them a certificate beyond 3 days of service (issued on the 4th day, handed in no later than 2 days after), and you send nothing to the CNS or the CMFEP.
The deadlines to remember
| Situation | Deadline | For whom |
|---|---|---|
| Tell your employer | 1st day of absence | Employer |
| Certificate with your employer | By the 3rd day of absence at the latest | Employer |
| Sick leave of 2 working days or less | No declaration | CNS |
| Sick leave of more than 2 working days | Before the end of the 3rd working day | CNS |
| Extension | Before the end of the 2nd working day after the planned return date | CNS |
| Deadline falling on a Saturday, Sunday or public holiday | Moved to the next working day | CNS |
Examples from the CNS. Your sick leave starts on a Friday: you send your certificate by the following Tuesday at the latest. Your first certificate ran until Tuesday, with a return on Wednesday, and it's extended: you send the new one by Friday at the latest. You work part time and fall ill on a Monday when you don't work: you tell your employer on Tuesday and send to the CNS by Thursday at the latest.
If you don't send your certificates to the CNS on time, you risk a fine.
The electronic certificate (eCIT)
If your doctor practises in Luxembourg and is equipped for it, they can issue an electronic certificate. You receive a notification in your private MyGuichet.lu space, you view the certificate, then you send it on:
- to the CNS, automatically (with a short window to cancel) or by approving each sending yourself;
- to your employer, online if they have a business space on MyGuichet.lu, otherwise on paper (the doctor can print it, or you print part 2 from your space).
If your employer hasn't seen the electronic certificate, give them a printed version to stay within the deadlines. You can always ask your doctor for a signed paper certificate. A certificate from a doctor abroad doesn't go through this system: it goes by post or through the CNS online form.
No access to MyGuichet.lu yet? Our sheet MyGuichet and LuxTrust explains how to log in.
Cross-border worker: your certificate comes from your country
You can be signed off by a doctor in your country of residence. The deadlines are the same, and your 13-digit Luxembourg identification number must appear on everything you send.
- France: since 1 July 2025, sick leave must be issued on the new secure paper Cerfa form, the only one the CNS accepts. Part 1 goes to the CNS, another part goes to your employer. You send it by post or as a legible scan via the CNS online form.
- Germany: the "Arbeitsunfähigkeitsbescheinigung" has a part 1 for the CNS and a part for the employer. Ask your doctor for a copy with the diagnosis and your Luxembourg number for the CNS, and a copy without the diagnosis for your employer.
- Belgium: most certificates only have one part. Ask your doctor for a duplicate for your employer.
Who pays you during sick leave?
Your employer first. They keep paying you your full salary until the end of the month in which you reach the 77th day of incapacity, counted over the previous 18 months. These are calendar days, weekends and public holidays included. In practice, that's 11 to 15 weeks depending on when the 77th day falls. If you change employer, the counter resets to zero.
Then the CNS. From the following month, the CNS pays you a sickness cash benefit. It's calculated on your basic salary and the average of your variable monthly bonuses, excluding overtime and benefits in kind, and it's capped at five times the social minimum wage. The CNS informs you and your employer when responsibility for payment changes.
The exceptions to know:
- During the first 3 months of your probation period, your employer keeps paying your salary from the first day, and the Mutualité des employeurs reimburses them in full.
- On a fixed-term contract, temping or during a notice period, your employer only pays you until the end of the contract.
- In the public sector, your pay continues throughout your sick leave.
- Self-employed, the rules are different: the benefit remains suspended until the end of the month of the 77th day, over 18 months. The Mutualité des employeurs can cover this period if you've joined it voluntarily.
What if your income drops?
For most employees, sick leave of a few days or weeks changes nothing on the payslip. The question arises in two cases: a salary above the cap of the CNS benefit (five times the social minimum wage), and the self-employed, who aren't paid during the first weeks without membership of the Mutualité des employeurs.
If you're in one of these cases, income protection insurance can bridge the gap. If you want peace of mind, an insurance advisor can look at your situation and call you back.
An advisor from the agency will call you back.During sick leave: going out and checks
- For the first 5 days, you're not allowed to go out, even if your certificate says otherwise.
- From the 6th day, unless your doctor forbids it, you can go out from 10 am to 12 pm and from 2 pm to 6 pm.
- Your medical appointments (doctor, treatment, Social Security Medical Board) are allowed at any time from the first day.
- No sport (unless medically advised), no activity incompatible with your condition, no café or restaurant, except for a meal announced to the CNS.
- Not at home during your sick leave? Give the address where you're staying on the certificate, or declare it to the CNS.
CNS inspectors can visit you between 8 am and 9 pm, from the first day, whether you're a resident or a cross-border worker. If you were out, you have 3 working days to justify yourself.
Going abroad during your sick leave requires prior authorisation from the CNS, granted only in specific cases (serious illness, for example). Without authorisation, the CNS can suspend your benefit.
Your protection against dismissal
If you told your employer on the first day and they received your certificate by the 3rd day at the latest, they can't dismiss you during your sick leave, even for gross misconduct, for 26 weeks at most from the start of the incapacity. These two obligations also apply to each extension.
The protection doesn't apply if you declared your illness after receiving the invitation to the preliminary interview or the dismissal letter, except for emergency hospitalisation (the certificate must then be presented within 8 days). A dismissal during the protection period is unfair: you have 3 months to take the case to the labour court.
After 26 weeks of uninterrupted sick leave, your employer can dismiss you, but they need a real and serious reason. For everything on dismissal, read our guide dismissal in Luxembourg.
The 78-week limit. The CNS pays at most 78 weeks of incapacity over a period of 104 weeks, counting all periods of sickness, occupational disease and work accident. According to the Labour and Mines Inspectorate (ITM), your employment contract ends automatically on the day you exhaust this entitlement. Our guide incapacity for work explains what happens before and after: redeployment, invalidity pension.
Common mistakes
Waiting for the certificate before telling your employer
You inform them on day 1, the certificate follows.
Seeing a doctor after the 3rd day
The CNS only counts your sick leave from the day you see the doctor, not before.
Sending to the wrong address
A certificate goes to the Indemnités pécuniaires (cash benefits) department, not the Remboursements (reimbursements) department.
Sending the same certificate online and by post
One sending is enough.
Cross-border worker in France
An old non-secure form is rejected by the CNS.
Going out during the first 5 days
Or outside the allowed hours: the CNS can issue warnings.
Frequently asked questions
No. If your incapacity doesn't exceed 2 working days, you have nothing to declare to the CNS. Your employer, however, must be informed from day 1 and can require a certificate from the first day.
Caisse nationale de santé, Indemnités pécuniaires, L-2980 Luxembourg, no stamp needed from Luxembourg. You can also send it as a PDF via the CNS online form.
Your employer, until the end of the month in which you reach 77 days of sickness over the last 18 months. After that, the CNS pays you a benefit, capped at five times the social minimum wage.
The CNS pays at most 78 weeks of incapacity over a period of 104 weeks. According to the ITM, the employment contract ends automatically when this entitlement is exhausted.
Not during the first 26 weeks, even for gross misconduct, if you told them on day 1 and they had your certificate on day 3. After that, they need a real and serious reason.
Yes, on the new secure Cerfa form. You send part 1 to the CNS (by post or as a scan via the online form) and the employer part to your employer, within the same deadlines.