Objective: To analyse the efficacy of two types of analgesia protocols during outpatient electromagnetic extracorporeal lithotripsy (ESWL) with a STORZ Modulith SLX second generation lithotriptor., Material and Methods: One hundred and seventy one patients were prospectively randomized to 2 groups. Group 1 (n-82) received 40 mg of Piroxicam IM, and group 2 (n=89) received 100 mg Tramadol IV Lithotripsy was performed in 2 sequences, T1 and T2, during which quantitative evaluation of pain (VE) was performed according to a VAS scale and qualitative evaluation of pain (QE) was performed according to the McGill questionnaire. Endpoints included the mean VE and QE pain scores at T1 and T2, the maximum power tolerated at T2, the postoperative pain at the 6th, 12th and 24th hours after ESWL, the pain score according to the power and according to the frequency and adverse effects. Comparisons were performed by analyses of variance (significant for p < 0.05)., Results: No significant difference was observed between the two groups for stone dimensions, duration and number of ESWL shots (p > 0.05) and significant difference was observedfor pain with the two drugs used. Pain was more severe as frequency and power increased. Only one intervention was stopped because of pain. Data analysis suggests that tramadol induces more adverse effects., Conclusion: Piroxicam and tramadol are two analgesics commonly used in clinical practice and both are suitable for the treatment of pain during outpatient extracorporeal lithotripsy.