BACKGROUND Opioid analgesics are used to relieve pain in patients with cancer and can improve their quality of life. This study aimed to investigate the efficacy and tolerability of high-dose (>150 mg/day) controlled-release oxycodone for the control of pain in patients with advanced solid malignant tumors. MATERIAL AND METHODS A retrospective clinical study was undertaken to include patients with advanced cancer treated at the Zhejiang Cancer Hospital who had treatment that included high-dose controlled-release oxycodone. The subjective numeric rating scale (NRS) for assessment of pain intensity (scores between 0-10) was used in all cases. RESULTS The study included 131 patients with advanced solid tumors with moderate to severe cancer pain. The mean NRS score before commencing high-dose controlled-release oxycodone was 7.10. The effective rate of relief pain was achieved in 90.1% (118/131) of patients, with an average effective dose of controlled-release oxycodone of 177.18±11.71 mg/day, resulting in a mean NRS of 2.15. There were 51 patients who achieved pain relief with mean treatment duration of 49.98±11.71 days. Combination therapy was required in 79 patients. Additional drugs included gabapentin (43 patients), pregabalin (10 patients) and non-steroidal anti-inflammatory drugs (NSAIDS) (26 patients). The main side effects of high-dose controlled-release oxycodone included constipation, nausea, vomiting, dysuria, dizziness, and drowsiness, but no patients discontinued treatment because of these. CONCLUSIONS This study showed that high-dose controlled-release oxycodone could effectively relieve moderate to severe cancer pain, without side effects that were severe enough to result in discontinuation of treatment.