In this case report, we tried to see the relationship between the continuous positive airway pressure (CPAP) adherence of obstructive sleep apnea (OSA) patient and the height of pillow. The patient was 41-year old female with OSA and had trouble adjusting to CPAP therapy due to the high pressure of the CPAP. We performed a overnight polysomnography for 8 hours in hospital and compared the apnea-hypopnea index (AHI) score and optimal CPAP pressure after changing the height of the pillow. The lower pillow setting had lower AHI score and lower optimal CPAP pressure which made the patient to feel more comfortable while sleeping. In conclusion, height of the pillow deserves consideration as a factor to promote CPAP adherence with lowering pressure, especially in the patients who are suffering with high pressure CPAP therapy.