To prevent endotracheal tube-related barotrauma or leakage, the intracuff pressure should be adjusted to 20–30 cm H2O. However, changes in the nasotracheal tube intracuff pressure relative to neck posture are unclear. In this study, we investigated the effect of head and neck positioning on nasotracheal tube intracuff pressure. Fifty adult patients with nasotracheal tubes who were scheduled for surgery under general anesthesia were enrolled. Following intubation, intracuff pressure was measured by connecting the pilot balloon to a device that continuously monitors the intracuff pressure. Subsequently, the intracuff pressure was set to 24.48 cm H2O (=18 mmHg) for the neutral position. We recorded the intracuff pressures based on the patients’ position during head flexion, extension, and rotation. The initial intracuff pressure was 42.2 cm H2O [29.6–73.1] in the neutral position. After pressure adjustment in the neutral position, the intracuff pressure was significantly different from the neutral to flexed (p < 0.001), extended (p = 0.003), or rotated (p < 0.001) positions. Although the median change in intracuff pressure was <3 cm H2O when each patient’s position was changed, overinflation to >30 cm H2O occurred in 12% of patients. Therefore, it is necessary to adjust the intracuff pressure after tracheal intubation and each positional change.