Refusing a breath test or blood test in Belgium: what are the consequences?

“I’m not blowing.” Some drivers think this is how to avoid a conviction: no measurement, no proof. That is wrong. An unjustified refusal is an offence in itself, and the law punishes it as severely as a high alcohol level. Yet not every refusal is punishable, and not everything that looks like a refusal actually is one.

This article complements our guide to drink driving.

You can refuse the “sniffer”

The sampling test, where you breathe towards a device without a mouthpiece, is a preliminary test. It is not required by law, and refusing it is not an offence. You then go straight to the breath test. Refusing therefore gets you nowhere.

The breath test, breath analysis and blood test: no

The breath test, breath analysis and blood test are governed by law. Anyone who refuses them without a legitimate reason commits an offence. The law treats this refusal as equivalent to an alcohol concentration of 0.35 mg/l of exhaled alveolar air (AAE) or more, the most serious category of alcohol intoxication.

The consequences are felt straight away:

• a temporary driving prohibition of 12 hours;
• immediate withdrawal of your driving licence for 15 days, see our article on immediate withdrawal;
• the police call in a doctor for a blood test, which you can in turn refuse, with the same consequences;
• as a rule, a summons (citation) before the police court (tribunal de police), where the judge can impose, in addition to a fine and a driving ban (déchéance du droit de conduire), an alcohol interlock (éthylotest antidémarrage).

What counts as a refusal?

A refusal is active opposition to the test. It does not have to be physical: saying that you will not blow is enough. The refusal is recorded in the police report (procès-verbal).

Some situations from practice:

• You run off. Anyone who leaves to avoid the test or the blood test is refusing.
• You are unconscious. Someone who is not conscious cannot refuse. After a serious accident, however, a blood test can follow.
• You do not blow hard enough. Anyone who tries but cannot blow hard enough, for example because of hyperventilation or a lung condition, is not refusing. A blood test then follows.
• You deliberately blow too weakly. Anyone who deliberately blows insufficiently can, on the other hand, be considered to be refusing. This is a factual assessment and is often disputed.

When is a refusal legitimate?

A refusal is not an offence if there is a legitimate reason. This is almost always a medical reason. An example: a person whose veins are calcified because of an illness, for whom a blood test is not reasonable.

It is first the doctor called in by the police who assesses whether the reason is legitimate. He or she examines the reason given, if you are or remain on the spot. In the end, the judge decides. Anyone with a medical reason must therefore state it clearly and be able to back it up later with documents.

Refusal in drug cases

For drugs, a comparable scheme applies (article 37bis, § 1, 5° of the Road Traffic Act (loi relative à la police de la circulation routière)). Refusing a saliva test, saliva analysis or blood test without a legitimate reason is an offence. In the event of a refusal, the police always call in a doctor, who checks whether there is a legitimate reason and takes blood if necessary.

The doctor sends his or her assessment in a sealed envelope to the public prosecutor (parquet), because it may be covered by medical confidentiality. Someone who genuinely cannot produce enough saliva is not refusing. Also see our article on saliva analysis and blood tests.

Is refusing ever a good idea?

Rarely. Anyone who refuses is treated as someone with a high alcohol concentration, without there being a measurement that might have been lower. With a breath analysis, you actually have rights that can work in your favour: a second analysis and a counter-analysis by blood test. See our article on the breath test and breath analysis.

The defence when prosecuted for refusal

If you are prosecuted for a refusal, there are several possible lines of defence:

• Was there really a refusal? What exactly does the police report say? Were you clearly asked to blow, and did you understand the request, for example where there was a language problem?
• Was there a legitimate reason? A medical reason must be examined and supported by evidence.
• Were the police entitled to test you? Were you in a public place, and were you driving or about to drive?
• Was the procedure followed? If you refused the blood test, was a doctor called in?

Frequently asked questions

Have your case reviewed

Have you been summoned to appear for a refusal? We examine exactly what happened and which defences are available. Contact us.

Law as at 28 September 2026. We update this article when the rules change.