Carbon monoxide poisoning, a public health problem of considerable significance, is a relatively frequent event today, resulting in thousands of hospitalizations annually. A 70-year-old lady was seen in the emergency department with a provisional diagnosis of carbon monoxide poisoning. The previous night, she slept in a tightly closed room heated with coal ember. She was found unconscious in the morning with poor ventilation. She had a rare presentation of popliteal vein thrombosis, pulmonary emboli, and possible tissue necrosis with carbon monoxide poisoning. Oxygen treatment with low-molecular-weight heparin (nadroparine) and warfarin therapy resulted in an improvement in both popliteal and pulmonary circulations. In conclusion, the presence of pulmonary emboli should be sought in patients with carbon monoxide poisoning.