Medical certificate 2026: new rules since January, and the first lessons from practice

Updated on 26 May 2026, by the editorial team at by Watson.

In late February, a business owner called us with a simple question: “My employee is reporting sick for the third time this year for one day, without a certificate. Am I now allowed to ask for one or not?” Until last year, the answer was a clear “no”. Since 1 January 2026, the answer is suddenly: “yes, in most cases”. Confusing. We have sorted it out for you.

At a glance

• From 1 January 2026, an employee can only be off sick twice per calendar year without a doctor’s certificate, instead of three times.
• SMEs with fewer than 50 employees can use their work rules or a CBA (collective bargaining agreement) to set their own threshold for when a certificate becomes mandatory, but this has to be set down explicitly.
• The relapse period for guaranteed pay (the employer-paid sickness pay for the initial period) rises from 14 days to 8 weeks (56 days). For employers, that is a significant financial improvement.
• The deadline for invoking medical force majeure drops from 9 months to 6 months of incapacity for work.
• For employers with 50 or more employees, a solidarity contribution of 30% now applies on the NIHDI sickness benefit during the first two months, for employees aged 18 to 54. NIHDI is the Belgian National Institute for Health and Disability Insurance.

What is changing about the medical certificate in 2026?

The federal government’s reinforced back-to-work policy came into force on 1 January 2026. For employers it brings three concrete changes: a stricter approach to sickness without a certificate, a longer relapse period for guaranteed pay and an adjusted procedure for medical force majeure. There is more in the pipeline as well: from 1 April 2026, working schedules will become more flexible, and from 1 June 2026 night work will be more broadly permitted.

We draw on the official communications of the FPS Employment, Labour and Social Dialogue (the Belgian Federal Public Service for Employment) and on what sector partners have reported over recent months. Plus what we have seen ourselves in the files passing through by Watson.

Rule 1: a maximum of two sick days per year without a certificate

Until the end of 2025, an employee could be off sick three times per calendar year for one day without having to submit a doctor’s certificate. From 1 January 2026, that becomes a maximum of two times per year.

In concrete terms:

• An employee reports sick for one day, on a Monday. He works for an employer with 50 or more employees. It is his third time this year. The employer may now ask for a doctor’s certificate, even for that single day.
• The same employee at an employer with fewer than 50 employees (an SME, small or medium-sized enterprise): it depends on the work rules or the CBA. See the next paragraph.

The exception for SMEs

For employers with fewer than 50 employees, an important nuance applies. Through the work rules or through a sectoral or company-level CBA, an SME can deviate from the new rule: either by keeping the exemption from a medical certificate at three times per year, or by requiring a medical certificate from the very first day of sickness.

This is not automatic. The SME has to set this down explicitly in its work rules, or rely on a CBA arrangement. If nothing is set down, the new default rule of two times applies.

Practical advice for SME employers:

• Check your work rules. Is there an explicit arrangement for sick days without a certificate? If so, how many days does it allow?
• Check your CBA. For many sectors, there is an arrangement at joint industrial committee level.
• If both are silent: the new rule of two times per year applies automatically.
• If you want to deviate from the standard two-day rule, your work rules need to be amended. Our experts will guide you through that consultation. The article [“HR policy in the second quarter: refreshing your work rules”] goes into this in more detail.

“The biggest pitfall in the first quarter: managers who assumed their old rule would automatically continue to apply, and only discovered in March that their work rules said nothing at all about sick days.”

What should an SME do today?

Three concrete steps.

Step 1. Pull out your work rules. If they have not been revised in recent years, you can expect that nothing specific is set down about this rule, which means you fall under the new default.

Step 2. Decide from how many days of sickness onwards you expect a medical certificate. There is no gold standard. That choice depends on the history of your organisation, your absence and well-being policy, and the need to safeguard continuity and workload.

Step 3. If you want to change something, have your work rules reviewed. That requires a procedure: announcement to your staff, collection of comments, waiting period, publication.

Rule 2: relapse period for guaranteed pay from 14 days to 8 weeks

For an employer, guaranteed pay is the obligation to pay a sick employee’s wages during an initial period (one month for white-collar workers, 30 days for blue-collar workers). After that period, the health insurance fund takes over.

The relapse period was 14 days until the end of 2025. If an employee fell ill again within 14 days of the end of a previous period of sickness, that counted as the same period of sickness. The employer therefore did not have to pay guaranteed pay a second time. Outside those 14 days, the counter started again at zero.

From 1 January 2026, that relapse period has been extended to 8 weeks (56 days). That is four times as long.

Before and after, in a worked example

Suppose employee A is off sick from 3 to 20 February 2026 inclusive (18 days). The employer pays guaranteed pay for that period. Employee A falls ill again on 15 April 2026, which is 8 weeks and 5 days after the end of the previous period of sickness.

For employers who see short, recurring absences, this is a significant financial improvement. The arithmetic is simple: the time window in which you do not have to pay guaranteed pay a second time has become four times wider.

What should an SME do today?

Step 1. Make sure your HR administration applies the new period correctly in payroll calculations. This is the biggest source of errors in the first few months: automated systems still set to 14 days.

Step 2. Check recent payroll calculations. Have you automatically paid guaranteed pay again on a relapse within 8 weeks since January? If so, you have overpaid. In principle, that can be recovered, although that is not always straightforward in legal terms.

Step 3. Communicate the rule to your team. An employee who understands why his pay differs between a first and a second period of sickness will ask fewer questions.

Rule 3: medical force majeure, shorter procedure

Briefly: the period for starting a medical force majeure procedure has been reduced from 9 months to 6 months of incapacity for work. This affects a specific scenario: employees on long-term sick leave with limited prospects of returning to work.

For an SME with one or several employees on long-term sick leave, it is useful to know about this procedure, but it follows a strict timeline and contains a fair number of conditions. A full explanation falls outside the scope of this article.

What stands out in the first few months of 2026?

Three patterns we see at by Watson, which sector organisations broadly confirm.

Signal 1: many SMEs have not amended their work rules. Result: their staff are unwittingly subject to the stricter two-times rule, while the manager assumed the old three-times rule still applied.

Signal 2: payroll calculations on auto-pilot. Payroll service providers have generally updated their systems on time. Payroll calculations on relapse therefore usually run correctly, but they do cause confusion among employees who do not always know the difference between a first and a second period of sickness.

Signal 3: unclear communication to staff. Employees often do not know that the rules have changed. Someone who is off sick for one day for the third time in 2026 and has not submitted a certificate sees it as an administrative detail. It is not: the employer has the right to ask for a certificate, and can take steps if it is refused.

What does by Watson do for employers?

We support SME employers with:

• Updating the work rules with the new sickness rules.
• Applying the 8-week relapse period correctly in payroll calculations.
• Communicating the changes to staff in clear language.
• Managing long-term sickness files and any medical force majeure procedures.
• Integrated advice where HR, accounting and tax meet (for example, replacing a sick employee and the financial impact of doing so).

Frequently asked questions

What if my employee reports sick for the third time this year without a certificate, and I am an SME with fewer than 50 employees? Look at your work rules or CBA first. Does either explicitly allow three times a year? Then you are fine. Is nothing set down? Then as an employer you may ask for a certificate. A refusal can even give rise to an unauthorised absence.

Am I required to amend my work rules? Not required, but advisable if you want to keep the three-times rule, or if you are reviewing other staff rules at the same time.

Is a sickness report via WhatsApp or email sufficient? For one day without a certificate: yes, an ordinary sickness report is enough. For longer absences, you have to receive a doctor’s certificate within the period agreed in your work rules (often 48 hours).

Does the 8-week relapse period also apply to a small employer? Yes. This rule is general, with no exception for SMEs.

What exactly is the 30% solidarity contribution? For employers with 50 or more employees, a solidarity contribution of 30% applies on the NIHDI sickness benefit during long-term sickness, for the first two months, for employees aged 18 to 54. This contribution does not apply to SMEs with fewer than 50 employees.

What else is changing in 2026 in employment law? Several things. From 1 April 2026, the rules on working schedules, voluntary overtime and part-time work will become more flexible. In addition, night work will be more broadly permitted from 1 June 2026. We will cover those topics in separate articles later this year.

Do your work rules need an update?

For SME employers we look in detail at the work rules, the CBA arrangements and the payroll processing. Where needed, we guide you through the update of your work rules. Schedule a conversation via bywatson.be/contact.