Objectives: to assess the outcome of preoperative compared with post-operative Piroxicam measured by the dose of Tramadol as post-operative pain relief. Patients and method: clinical randomized controlled trial. 60 patients underwent ureter and kidney stones surgeries at Viet Duc hospital, divided into 2 groups. Group I: 30 patients with Piroxicam 2 hour before surgery, group II: 30 patients with Piroxicam immediately after surgery. Results: Group I need Tramadol with mean duration 93.53 + or - 38.06 minutes, longer than group II with 64.93 minutes with p0.05. The mean dose of Tramadol for group I is 78.3 + or - 38.6, which is lower than group II 123.3 + or - 38.1. Conclusion: Pre-operative Piroxicam is more effective compared with post-operative administration.