Background: Offering human papillomavirus-based self-sampling to nonparticipants in routine cervical cancer screening can increase screening participation. However, little is known about characteristics of women who accept self-sampling. In this population-based study, we investigated determinants for participation in self-sampling among Danish nonattenders to routine cervical cancer screening.Methods: During 2014 to 2015, a random sample of screening nonparticipants ages 27 to 65 years living in the Capital Region of Denmark were invited for self-sampling. Of 21,314 eligible women, 4,743 participated in self-sampling. Information on sociodemographic characteristics and mental and physical health of all the women was obtained from nationwide registries, and 3,707 women completed a questionnaire on lifestyle, sexual behavior, and reasons for nonparticipation in routine screening. We used logistic regression to estimate ORs for participation in self-sampling, crude, and adjusted for sociodemographic characteristics.Results: Basic education [ORadjusted = 0.79; 95% confidence interval (CI), 0.72-0.88], low income (ORadjusted = 0.66; 95% CI, 0.59-0.73), origin from a nonwestern country (ORadjusted = 0.43; 95% CI, 0.38-0.48), and being unmarried (ORadjusted = 0.66; 95% CI, 0.61-0.72) were associated with lower self-sampling participation. Long-term unscreened women (ORadjusted = 0.49; 95% CI, 0.45-0.53), women with prior schizophrenia or other psychoses (ORadjusted = 0.62; 95% CI, 0.48-0.80), women with poor self-perceived health (ORadjusted = 0.42; 95% CI, 0.25-0.69), and women who perceived screening as unnecessary (ORadjusted = 0.54; 95% CI, 0.37-0.80) or irrelevant (ORadjusted = 0.81; 95% CI, 0.78-0.96) were less likely to self-sample.Conclusions: Certain population groups, including women with low socioeconomic position or of nonwestern origin, were less likely to participate in self-sampling.Impact: Targeted approaches may be needed to increase screening participation in these groups. Cancer Epidemiol Biomarkers Prev; 27(11); 1342-51. ©2018 AACR.