Purpose: The aim of this study was to present our experiences with intrathecal morphine used for postoperative analgesia in the patients underwent thoracic surgery in our clinic.Materials and Methods: In this study, a total of 18 adult patients who underwent thoracic surgery and were administered intrathecal morphine for postoperative analgesia between January 2020 and June 2020 were evaluated retrospectively. The patients were divided into two groups: Group 1; 10 mcg/kg intrathecal morphine grup, Group 2; 7 mcg/kg intrathecal morphine group. Demographic data, doses of morphine administered, duration of surgery and anesthesia, intraoperative anesthetic agent consumption, postoperative hemodynamic variables, pain scores, additional analgesic requirement and side effects were recorded.Results: Twelve of the patients (66.7%) were administered 10 mcg/kg and 6 of them (33.3%) 7 mcg/kg intrathecal morphine according to ideal body weight. Intraoperative anesthetic agent consumption was found to be lower in Group 1 compared to Group 2, but this difference was not statistically significant. Pain scores at rest were statistically lower in Group 1 at 12, 24 and 48 hours postoperatively. Pain scores at effort were also statistically lower in Group 1 at 12, 18, 24 and 48 hours postoperatively.Conclusion: Intrathecal morphine is a safe postoperative analgesia option for thoracic surgery patients. We believe that intrathecal morphine at a dose of 10 mcg/kg provides more effective analgesia than 7 mcg/kg without increasing the frequency of side effects.