Luxembourg has become the third European Union country, after the Netherlands and Belgium, to decriminalise voluntary euthanasia.
Terminally ill people will be able to have their lives ended after receiving the approval of two doctors and a panel of experts.
Last year, Luxembourg became embroiled in a constitutional crisis when Grand Duke Henri refused to sign the euthanasia bill into law. The crisis led to his power being curtailed and laws no longer need to be signed by him.