In most countries, urine tests are required for opioid agonist treatment (OAT). Whilst Swiss federal law does not require urine tests as part of OAT follow-up, several Swiss cantons either request or recommend them. This article presents a viewpoint previously published in a French and a French/German paper supported by Swiss associations of addiction professionals. The article questions the legal and medical justification for such tests in connection with OAT. The flaws of urine testing as a clinical assessment tool are discussed, as well as the potentially negative impact on the therapeutic process for opioid dependence. In line with a person-centred approach, recommendations include removing the obligation from any remaining legislation and limiting tests to situations where the person in treatment has requested them.