After liver transplantation, respiratory complications are frequent. The purpose of this study was to assess if intraoperative monitoring of respiratory compliance is of clinical value in predicting such complications. Respiratory compliance was continuously monitored with a side-stream respiratory gas flow and pressure sensor (Datex, Helsinki, Finland) at the endotracheal tube in 18 adult patients undergoing orthotopic liver transplantation without veno-venous bypass. Respiratory compliance decreased along with blood volume expansion under anaesthesia before the start of surgery (P < 0.05). Compliance improved as ascites was removed at the beginning of laparotomy (P < 0.001). The highest compliance values were seen during liver surgery. In the patients without ascites preoperatively, compliance was lower at the end of surgery than at anaesthesia induction (P < 0.001). In the patients with ascites, compliance at the end of surgery was equally low as at anaesthesia induction. Compliance at the end of surgery was lower in the patients with bilateral than in those with right-sided or no pleural effusions in the postoperative chest X-rays (P < 0.001). In conclusion, intraoperative monitoring of respiratory compliance is one useful method for clinical use in predicting postoperative bilateral pleural effusions.