Background: non-anesthesiologist administration of propofol (NAAP) using continuous infusion systems may achieve a more sustained sedative action., Aim: to compare intermittent boluses (IB) with pump continuous infusion (PCI) for NAAP, targeted to moderate sedation, for colonoscopy., Methods: 192 consecutive outpatients were randomized to receive IB (20 mg propofol boluses on demand) or PCI (3 mg/kg/h plus 20 mg boluses on demand). Sedation could be stopped at cecal intubation at the discretion of the endoscopist. Satisfaction rates of the patient, nurses and endoscopist, propofol doses, depth of sedation (at the beginning, at cecal intubation and at the end), recovery times, complications and were collected., Results: there were no differences between groups regarding patient, nurse or endoscopist satisfaction rates with procedural sedation. Propofol doses (mg) were significantly higher during the induction phase -86 (30-172) vs. 78 [30-160], p 0.03- and overall -185 (72-400) vs. 157 (60-460), p = 0.003- for PCI group. 81 % of assessments of the depth of sedation were moderate. The level of sedation (O/AAS scale) was borderline significantly deeper at cecal intubation (2.38 vs. 2.72; p = 0.056) and at the end of the procedure (4.13 vs. 4.45; p = 0.05) for PCI group, prolonging thus early recovery time (6.3 vs. 5.1 minutes, p = 0.008), but not discharge time. Complications, all of them in minors, were non-significantly more frequent in the PCI group (9 vs. 7 %, p = 0.07)., Conclusions: NAAP for colonoscopy was safely administered with comparable satisfaction and complication rates with either IB or PCI.