Transtracheal oxygen therapy (TTOT) is applied particularly to patients with chronic obstructive pulmonary disease. We treated four patients in a preterminal stage of their disease, the primary diagnoses being pulmonary fibrosis and bronchoalveolic carcinoma. Oxygen administered by nasal delivery devices had been inefficient in all patients. TTOT reduced dyspnoea, improved exercise tolerance and reduced hospital stay. We conclude that TTOT has a potential for being medically beneficial in a preterminal stage of pulmonary fibrosis and carcinoma.