Radiotherapy is crucial in the management of cancer patients in both the curative and palliative settings. However, patients often report pain both during positioning for, and execution of, radiotherapy and this may be a reason for interrupting the radiotherapy session. This observation is common even if the patient is undergoing baseline drug therapy for cancer pain. Recent data suggest that orally administrated immediate-release morphine (MIR) is able to reduce pain in patients with predictable pain. The authors tested a rescue dose of MIR 10 or 20 mg, 20 to 60 minutes before radiotherapy, to verify the effectiveness of MIR in this setting and also to assess the patient's ability to receive the full course of radiotherapy. One hundred forty consecutive patients were evaluated during radiotherapy treatment and visual analogue scale (VAS) and positioning VAS scores were assessed. All patients completed the course of scheduled radiotherapy and pain was well controlled, despite the fact that previous pharmacological treatment had not been able to completely control chronic cancer pain. These data strongly suggest a role for MIR pretreatment in patients with pain due to positioning during radiotherapy.