The presence of oxygen in the β-ionone formation reaction from the carotenoid degradation process in crude palm oil samples has been investigated. Carotenoid compounds in crude palm oil samples were degraded with variations in air of 8 L/h, 12 L/h, 16 L/h, and 20 L/h. The oxygen percentage can be calculated based on the ratio of oxygen and nitrogen in the air. The degradation process was carried out at the same temperature, namely 140 o C for 2 h. To observe the effect of oxygen levels during the carotenoid degradation process to produce β-ionone, several parameters have been pointed, including carotenoid levels in CPO before and after the degradation process using a spectrophotometer, the color of the CPO solution before and after degradation using the color flex hunter lab and the β-ionone levels resulting from the degradation of Carotenoids by gas chromatography using a mass spectrometry detector. As a result, it can be mentioned that the presence of oxygen has influenced the degradation process of carotenoids in CPO. More carotenoids are degraded with greater the amount of oxygen. The most excellent degradation process was obtained at 80%. However, β-ionone was only detected in the air flow treatment of 20 L/h with a value of 0.44 mg/L. The results of this study showed that the amount of oxygen dramatically influences the formation of β-ionone when the carotenoid degradation process is carried out under hot conditions. These data can be used to develop β-ionone formation technology for future industrial-scale applications.