Belgian cross-border workers

Applicable rules

The insured person is considered a cross-border worker if they work (and are insured) in a different EU country than the one they reside in and under the condition that they return to the country of residence every day or at least once a week. In this case, the country competent in social security matters is the country where they work.

Use of the BL1 form

The BL1 form is a document of legal entitlement to healthcare benefits delivered by the competent country (country where contributions are payed) and allows registration in the country of residence. In this case, healthcare is delivered in the country of residence as if the concerned person was insured there. The BL1 form delivered by the competent healthcare fund must be presented to the health fund in the country of residence. The healthcare fund from the country of residence confirms the registration of the form to the competent healthcare fund.


The cross-border worker insured in Luxembourg must register with the health insurance fund of their place of residence in order to benefit from healthcare reimbursements. The CNS issues a document of entitlement for this purpose: the BL1 form, as provided for in the Belgium-Luxembourg agreement of 24th March 1994.

Following registration as a cross-border worker from Belgium, the BL1 form is normally sent automatically to to the private address of the insured person, who should present the form to a Belgian health insurance fund of their choice.

If the insured person does not receive the BL1 within fifteen days following the submission of the declaration of entry to the CCSS (Joint Centre for Social Security) they are advised to order the BL1.

As per article 5 of the Belgium-Luxembourg agreement of 24th March 1994, the cross-border worker and members of their family who are entitled to benefits in kind on Belgian territory enjoy the right, where applicable, to full reimbursement under Luxembourg law.

For full information concerning complementary reimbursements, the insured person can contact their Belgian health insurance fund (mutuelle) or the CNS, as the case may be.


The cross-border insured and the members of their family are entitled to the same benefits under the same terms and conditions as those to which the residents of the Grand Duchy of Luxembourg are entitled.

The law of the insured's country of residence applies concerning the determination of who qualifies for benefits in their capacity as a member of the insured's family.

For this purpose, the Belgian insurance fund (mutuelle) transmits a document of entitlement to the CNS attesting to the fact that members of the family are co-insured in the name of the person insured in Luxembourg.

Certificate of incapacity for work

In case of sickness or accident, the insured person must send the original certificate of incapacity for work directly to the CNS before the end of the third working day that the insured has been on sick leave as a result of the doctor’s findings.

In order to speed up the administrative procedure and to assure a smooth procedure for the remittance of sickness benefits, it is recommended that all documents sent to the CNS include the insured person's individual Luxembourg identification number.

In this regard, it is recommended to ask the doctor to indicate the Luxembourg national identification number, or, if necessary, to mark it themselves on the back of the medical certificate.

Coverage of healthcare received in the country of residence

With regard to reimbursement of healthcare, treatment provided in the country of residence can only be reimbursed by the country of residence according to its own rates, tariffs and terms.

Only Belgian cross-border workers and former Belgian cross-border workers benefit from a specific regime based on the provisions of the Belgium-Luxembourg agreement of 24 March 1994.

This agreement specifies that the CNS will provide an additional reimbursement for treatment provided in Belgium at the level of the average reimbursement rate in Luxembourg (currently 94.4% ).

The Belgian healthcare fund transmits the necessary information for the complementary reimbursement.

Coverage of healthcare received in a country other than Luxembourg or other than the country of residence

Necessary/emergency treatment is paid for based on the European Health Insurance Card/EHIC (or if necessary a replacement certificate) issued by the competent country.

Planned inpatient treatment is subject to a prior authorisation from the Medical Board of the Social Security (Contrôle médical de la sécurité sociale - CMSS) and can only be reimbursed if approval is granted. If S2 authorisation is granted by the competent country, the treatment will be paid for by the country where it is provided according to the rates and tariffs applicable there. If the insured person was given a "directive" authorisation from the competent country, the insured person advances the cost and is reimbursed by the competent country according to the rates and tariffs in force there.

Please note that for some ambulatory healthcare, a prior approval by the CNS on the basis of a positive advice by the CMSS is mandatory.

Planned outpatient treatment is paid for by the competent country according to the rates and tariffs in force there.


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