BACKGROUND: Although ventilatory therapy after liver transplantation is essential part of postoperative intensive care, the appropriate time of extubation remains controversial. Thus we constructed an indigenous index to determine the timing of early or delayed extubation. This experiment was undertaken to decide on whether the index adequately serves as a guideline for the time of extubation. METHODS: We divided factors that affect the time of extubation into two categories-preoperative and intraoperative. Using these categories, we examined 68 patients scheduled for liver transplantation. The preoperative categories were Child-Pugh Class, preoperative creatinine level, and preoperative O2/FiO2 ratios. The intraoperative categories included the amount of packed red cell transfused and oliguria after liver reperfusion. We categorized our patients into an early extubation group and delayed extubation group, according to the existence of these factors. Then we compared the variance of duration of mechanical ventilation and duration of ICU stay of the two groups. RESULTS: The duration of mechanical ventilation in the early extubation group was significantly shorter than in the delayed extubation group (P < 0.05). However, there were no significant differences in terms of duration of ICU stay or O2 index. Child-Pugh Class, preoperative hypoxemia, and the intraoperative amount of transfusion factors showed statistical significance (P < 0.05), but preoperative renal function and oliguria after liver reperfusion showed no significant difference between the two groups. CONCLUSIONS: The process of categorizing early and delayed extubation group by examining danger factors can indeed provide an appropriate guideline for respiratory care after liver transplantation by preventing premature or excessive extubation.