Introduction: Propofol has been profusely used for sedation in endoscopic procedures. In therapeutic procedures, such as endoscopic retrograde chonlangio pancreatography (ERCP), the general practice for sedation is to administer midazolam and petidine under the control of the endoscopist or sedation supervised by anaesthesiologist. Nurse-assisted propofol sedation in ERCP could be cost-effective and safe method. Aims & Methods: From November 02 to April 05 Propofol or Midazolam + Propofol were used as a sedation during ERCP procedures. A nurse was assigned to assist and control the sedation. Propofol boluses, plus Midazolam in some cases, followed by a continuous pump infusion of propofol were administered. Data prospectively recorded were: age, gender, ASA, therapeutic or diagnostic ERCP (and type), tolerance, endoscopist assessment of ERCP feasibility, arterial pressure, cardiac frequency and minimum oxygen saturation. Significant and minor complications during the procedure were recorded. Results: 506 patients whit mean age 72.1 (31.8% > 80 years old), 48.6% females were included in this study. Therapeutic ERCP (papillotomy, stone removal or stent insertion) was performed in 75.7% and 49.6 were ASA 3-4. Mean dose of propofol was 232 ± 120 mg. Midazolam (1-5 mg) was administered in 16.4%. Tolerance, rated by the patient was good or very good in 98% and ERCP feasibility was good or very good in 96%. Sat O2 < 90 occurred in 13%, BP < 90 in 3.4%, tachycardia in 20.1% (2.4% >120 bpm), and episodes of bradichardia <50 in 0.8%. Overall significant complications occurred in 31 patients (6.1%) with 34 events. Only in one case endoscopy removal and resuscitation measures were necessary. Furthermore, there have been 16 oxigen desaturatuions (47.1%), 6 vomits (17.6%), 4 requiring secretion aspiration. In addition, there were 12 events (35.3%) of significant hemodinamic instability (7 tachicardia, 3 hypotension and 2 bradichardia). Neither intubation nor anesthesic assistance were required in any case. Unespectedly, episodes of hypotension, taquichardia, Sat O2 <90 or significant complications were not more frequently in patients ASA 3-4 or aged >80. Conclusion: Nurse-assisted Propofol-pump infusion is safe and most likely, a cost effective method of sedation during therapeutic ERPC even in high ASA grade or elderly patients