Background and study aims: A new colonoscope (XCFQ-160AW prototype, Olympus, Tokyo, Japan) has been developed, designed with an additional passive bending function to ease intubation through the left colonic flexure. In this study we investigated whether this function could be included in a standard colonoscope without jeopardizing general performance, particularly passage through the sigmoid colon. Patients and methods: 280 outpatients referred for routine colonoscopy at Telemark Hospital were randomly allocated to colonoscopy with a standard colonoscope (Olympus 140 series) or the XCFQ160AW prototype. Sedation was given on demand. End points were cecal intubation and the patients’grading of pain in a questionnaire. Results: Cecal intubation rates were 85 %and 87 %for standard and prototype endoscopes, respectively (P=0.57). On-demand sedation was given to nine (7%) and 15 (11%) of the patients, respectively (P=0.17). Of the patients, 256 (85%) returned their questionnaire,with 87 (63%) in the standard group and 109 (77%) in the prototype group reporting that they had experienced ‘no pain/slight pain’(P < 0.001). In a multiple logistic regression analysis, this difference in experienced pain remained statistically significant after adjustment for interendoscopist variation and the use of the endoscope-stiffening function. Two patients in the study, in whom there had previously been several unsuccessful attempts at negotiating the splenic flexure, were successfully examined with the prototype colonoscope. Conclusion: Examination with the Olympus XCF-Q160AW prototype with a passive bending function caused less pain than use of a standard Olympus 140 series colonoscope, without compromising other endoscope functions for colonic intubation. Background and research aims: A new colonoscope (XCFQ-160AW prototype, Olympus, Tokyo, Japan) has been developed, designed with an additional passive bending function to ease intubation through the left colonic flexure. In this study we enabled whether this function could be Patients and methods: 280 outpatients referred for routine colonoscopy at Telemark Hospital were randomly assigned to colonoscopy with a standard colonoscope (Olympus 140 series) or the XCFQ160AW prototype. Sedation was given on demand. End points were cecal intubation and the patients’ grading of pain in a questionnaire. Results: Cecal intubation rates were 85% and 87% for standard and prototype endoscopes, respectively (P = 0.57). On-demand sedation was Of the patients, 256 (85%) returned their questionnaires, with 87 (63%) and 15 (11%) of the patients, respectively %) in the standard group and 109 (77%) in the prototype group reporting that they had experienced ’no pain / slight pain’ (P <0.001). In a multiple logistic regression analysis, this difference in in pain pain statistically resistance after adjustment for interendoscopist variation and the use of the endoscope-stiffening function. Two patients in the study, in whom there had previously been several unsuccessful attempts at negotiating the splenic flexure, were successfully examined with the prototype colonoscope. Conclusion: Examination with the Olympus XCF -Q160AW prototype with a passive bending function caused less pain than using a standard Olympus 140 series colonoscope, without compromising other endoscope functions for colonic intubation.