PurposeMany people do not participate in mail-out bowel cancer screening programs due to difficulties using the screening kit. The current study investigated the ways the screening kit could be modified to improve usability.Methods1,109 people evaluated 15 different screening kit modifications. Participants reported on how these kit modifications would affect their screening barriers, their future screening intentions, and how much they would recommend that the modification is made to the current screening kit used the program. All responses were given via an online survey conducted between April and December of 2021.ResultsSeventeen percent of previous NBCSP non-participators indicated that aone-sampletest would increase their intention to participate. Recommendation ratings demonstrated higher levels of support for modifications that included providing a barcode naming label (M= 9.06, 95% CI [8.81, 9.31]), having a larger diameter opening of the collection tube (M= 8.42, 95% CI [8.10, 8.74]), and highlighting the expiry date on the kit packaging (M= 8.59, 95% CI [8.29, 8.89]). There were lower levels of support for modifications that reduced the size of the packaging the kit is sent in (M= 6.47, 95% CI [6.09, 6.85]), removed branding from kit packaging (M= 5.98, 95% CI [5.57, 6.39]), and removed the information booklet that comes with the screening kit (M= 5.25, 95% CI [4.78, 5.72]).ConclusionThese findings highlight multiple ways in which bowel cancer screening kits can be changed to increase usability for invitees of national bowel cancer screening programs. Findings have implications for all screening programs that use immunochemical-based bowel cancer screening kits.Supplementary InformationThe online version contains supplementary material available at 10.1007/s10552-023-01695-x.