Oxygen is the main treatment of carbon monoxide (CO) poisoning. In two simultaneous cases, the efficacy of conventional and continuous positive airway pressure (CPAP)-administered oxygen therapy was compared. A 63-year-old man and his 58-year-old wife were brought to the emergency department with complaints of dizziness, headache, and nausea. The man had a history of congestive heart failure and additionally had shortness of breath. Initial carboxyhemoglobin (COHb) values were 26% in the male patient and 24% in his wife. For the female patient, oxygen therapy was performed with a reservoir balloon mask; a CPAP device was used for the male patient. The COHb levels decreased below five percent after approximately two hours in the male patient and at the end of five hours in his wife. In follow-up, symptomatic relief was achieved in both patients and no additional complications were observed. According to our experience, CPAP ventilation can be a new and effective method for oxygen therapy in CO poisoning.