Before you start

City registration and a national register number
A Belgian bank account for reimbursements
S1 or E104 form from your previous EU health insurer, if you have one
Employment, self-employment or student status, which determines how contributions are collected

Step-by-step

1
Choose a ziekenfonds and join
CM, Solidaris, the liberal and neutral funds, the independent funds such as Helan and Partenamut, or the free public fund HZIV/CAAMI. Statutory cover is identical everywhere; they differ on complementary benefits, service and the small monthly contribution. Nobody enrols you — not your employer, not the university, not the city.
In personWho: YouWeek 1–3
2
Hand over your S1 or E104 if you were insured in the EU
These forms carry prior cover across and prevent a fund applying a waiting period before entitlement begins. Ask your old insurer for the form before you leave — obtaining it afterwards is much slower and occasionally impossible.
In personWho: You
3
Register a global medical file (globaal medisch dossier) with one GP
Nominating a single GP to hold your GMD raises the reimbursement on GP consultations substantially and gives you a doctor holding your whole record. It costs you nothing — the fund pays the GP an annual fee for keeping it — and it is the highest-return few minutes in the Belgian system.
In personWho: YouFirst GP visit
4
Do not use the university hospital as your first port of call
UZ Leuven is a tertiary referral centre, which means it exists for the complicated cases the rest of the system sends it. For ordinary illness a GP is faster, cheaper and the intended route, and out of hours 1733 puts you through to the on-call GP service rather than an emergency department. Using the big hospital for something a GP can handle costs you more and clogs a national resource.
OnlineWho: You
5
Check whether a specialist is geconventioneerd
Doctors who have signed the national fee agreement charge the official tariff; those who have not may add supplements your reimbursement does not cover. The proportion varies by speciality, it is published, and it is a question to ask when booking rather than at the desk afterwards.
OnlineWho: You
6
Take hospitalisation insurance before you need it
Statutory cover handles most hospital costs, but a private single room can carry very large room and fee supplements. Hospitalisation insurance via your ziekenfonds, an insurer or your employer is the standard Belgian answer and is far cheaper taken in advance.
OnlineWho: You

Documents you’ll need

eID and national register number
Belgian bank account details
S1 or E104 from a previous EU insurer
Employment contract, enrolment certificate, or self-employed social insurance affiliation
Vaccination records for children entering Flemish schools

Things most newcomers don’t know

Compulsory does not mean automatic — you have to join a fund yourself.

Your employer registers you for social security, which funds the system, but the ziekenfonds that actually reimburses you is a separate membership you take out. Until you have, you carry the full cost of treatment. International students and visiting researchers, who arrive in Leuven in very large numbers each September, are the group this catches hardest — many assume the university's registration covers it, and it does not.

Source: RIZIV/INAMI

Having one of Belgium's biggest hospitals next door is not the same as it being your GP.

UZ Leuven is a tertiary referral centre serving patients from across the country, which is excellent if you need something complicated and irrelevant if you have a chest infection. The Belgian system is built on the GP as the entry point, the global medical file makes that cheaper, and 1733 covers evenings and weekends. Arrivals from countries where the hospital is the default point of care use it that way here and pay more for a longer wait.

Source: RIZIV/INAMI; community-reported

The globaal medisch dossier is free and raises your GP reimbursement immediately.

Nominating one GP to hold your GMD increases the refund rate on GP consultations, improves continuity because that doctor holds your full record, and costs you nothing because the fund pays the GP for maintaining it. It also makes out-of-hours cover and specialist referrals smoother. It is the cheapest optimisation in the Belgian system and a large share of foreign residents never hear of it.

Source: RIZIV/INAMI

Flanders levies its own long-term care contribution on top of the federal system.

The Flemish social protection scheme charges an annual care contribution on adults registered in Flanders and funds care budgets for long-term dependency and disability. It is a Flemish Community matter, so a resident of Leuven is treated differently from a resident of Brussels — a real distinction in a city where a great many people work in Brussels and live here. It is small, it is separate from your ziekenfonds contribution, and arrivals frequently mistake the bill for an error.

Source: Flemish Community