Background/aim: The aim of this study was to quantify the changes in middle ear pressure (MEP) during robot-assisted radical prostatectomy (RARP). Materials and methods: Thirty patients undergoing RARP were included in this study. MEP was obtained at the following time points: awake (T1), postintubation (T2), pneumoperitoneum + 1 h of Trendelenburg position (T3), pneumoperitoneum + 2 h of Trendelenburg position (T4), pneumoperitoneum + 3 h of Trendelenburg position (T5), desufflation + supine position (T6), and 1 h after extubation in the postanesthesia care unit (T7). Heart rate, mean arterial pressure (MAP), peak airway pressure (PAP), tidal volume, minute ventilation, EtCO2, and blood gas values were recorded. Results: MEP was significantly higher at T4, T5, T6, and T7 as compared to T1 values. PAP values were significantly increased at T3, T4, and T5 compared to T2. MAP values at T3, T4, and T5 were significantly higher compared to T1. PaCO2 increased significantly at T4, T5, and T6 and pH decreased significantly at T4 and T5 when compared to T2. Conclusion: The combination of steep Trendelenburg position and pneumoperitoneum during RARP caused a significant increase in MEP, PaCO2, and EtCO2 levels. This propensity for increased MEP may cause problems in patients with preexisting ear disease.