Abstract: Objectives: To examine public perceptions of and preferences for colonoscopy vs. CT colonography (CTC) as technologies for colorectal cancer (CRC) screening.Methods: Six discussion groups were carried out with 30 adults aged 49–60 years (60% female). Information about different aspects of the tests (e.g. sensitivity, practical issues) was presented sequentially using a semi-structured, step-by-step topic guide. Discussions were recorded and analyzed using framework analysis.Results: CTC was favored on the parameters of invasiveness, extra-colonic evaluation and interference with daily life, whereas sensitivity, avoiding false-positives and the capacity to remove polyps immediately were perceived to be important advantages of colonoscopy. Ultimately, there was no strong preference for either test: with 46% preferring colonoscopy vs. 42% for CTC.Conclusion: With comprehensive information, colonoscopy and CTC were seen as having different advantages and disadvantages, yielding no clear preferences between the two. The sensitivity of colonoscopy was a decisive factor for some people, but the lower invasiveness of CTC was seen as an asset in the screening context.Practice implications: CTC may be an acceptable alternative to colonoscopy in CRC screening. Healthcare professionals working in the screening context should be sensitive to the range of characteristics that can determine preferences for CRC screening tests.