BACKGROUND Mechanical ventilation may relieve symptoms and prolong life for patients with amyotrophic lateral sclerosis, but may also prolong suffering. More knowledge is needed on ethical, legal and medical aspects upon termination. METHODS Two cases are discussed in light of relevant laws and literature, as well as the authors' own research and clinical experience. RESULTS A patient who had first declined life-sustaining treatment eventually chose to undergo tracheostomy. He later approached a locked-in state and wanted to terminate the treatment. Another patient reported poor quality of life and wanted to die, but declined to make a statement on refusal of resuscitation in case of an emergency. He was later resuscitated from CO2 narcosis and received non-invasive ventilation. He repeated that he wanted to die, but did not decide to terminate the ventilator until he was offered palliative treatment. Both patients received morphin and anxiolytics, and died shortly after the ventilator was withdrawn. CONCLUSIONS Mechanical ventilation can be terminated in line with good medical and ethical standards, and will then usually be legal. Patients have a legal right to refuse life-sustaining treatment, but not everybody want to make decisions regarding their own death. Fear of conducting euthanasia may prolong the patient's death process and prevent adequate palliative treatment.