This study will investigate whether cervical cancer screening among under-screened women could be improved with testing for human papillomavirus (HPV) using at-home self-collection kits delivered by mail. Invasive cervical cancer (ICC) is preventable through regular screening and treatment, but one fifth of US women report not receiving Pap testing at recommended intervals. More than half of ICC cases occur in these under-screened women. For women 30 years and older, the US Preventive Services Task Force recommends Pap smears alone every 3 years or physician-collected HPV testing with Pap smear (co-testing) every 5 years. Self-collection for HPV testing is a valid and well-accepted method for detecting HPV infection with comparable sensitivity and specificity to physician-collection for detecting high-grade cervical lesions. This 2-arm randomized control trial of 870 women will investigate whether offering HPV testing by mailed at-home self-collection to under-screened women increases their likelihood of completing cervical cancer screening. All participants will received an enhanced reminder by phone: a phone call providing (i) education on cervical cancer, and (ii) assistance scheduling an appointment for free screening at a study- affiliated clinic, if needed. Those randomized to the intervention arm will be mailed kits to self-collect cervicovaginal samples, return the samples for oncogenic HPV testing, and receive their results during the enhanced reminder call. HPV negative women will be considered screening complete and not receive scheduling assistance for in-clinic screening. Screening completion will be defined as in-clinic screening or a negative HPV self-collection result. Aim 1. Determine whether at-home HPV self-collection increases completion of cervical cancer screening among under-screened women offered enhanced reminders. Activities: We will recruit 870 under-screened, low-income women ages 30-64; randomize them to intervention (self-collection plus enhanced reminders) or control (enhanced reminders alone); and compare cervical cancer screening completion between the arms. Aim 2. Examine possible mechanisms explaining the intervention's effect, or lack of an effect. Activities: We will compare in-clinic screening completion between women who receive HPV-positive self-collection results, those who do not return a kit, and the control arm. We will assess perceived risk of cervical cancer pre- and post-intervention in all women, and examine psychological mediators of completing in-clinic screening. Aim 3. Estimate the incremental cost per additional woman completing screening of adding at-home HPV self- collection to enhanced reminders. Activities: We will measure economic inputs for each arm and calculate the incremental cost of at-home HPV self-collection per additional woman completing screening. If at-home HPV self-collection increases screening among under-screened women, it has potential to influence future outreach and clinical practice. Increasing early detection and treatment of high-grade precancerous cervical lesions will have a major public health impact by reducing suffering and death from ICC nationwide.