IntroductionTreatment with pelvic external beam radiotherapy with brachytherapy (EBRT/BT) for gynecological cancers may cause sexual dysfunction because of vaginal shortening and tightening. Regular vaginal dilator use is thought to reduce vaginal shortening and/or tightening, but compliance is poor. AimsThis study identified determinants of patients' adherence with dilator use after EBRT/BT. MethodsSemi-structured interviews were conducted with 30 women, aged 32-67 years, treated with EBRT/BT for gynecological cancers at two university medical centers in the past 36 months. Transcriptions were coded and analyzed with N-Vivo software. Main Outcome MeasuresDeterminants of dilator use were clustered based on the Health Action Process Approach, which describes (i) motivation processes that lead to a behavioral intention and (ii) volition processes that lead to the initiation or maintenance of actual behavior. ResultsAlmost all women attempted to perform long-term regular vaginal dilator use. Intended dilator use was determined by the expectation that it would prevent the development of vaginal adhesions and stenosis. Planning dilator use and making it part of a routine, using it under the shower, using lubricants, a smaller dilator size, or vibrators helped women. Others reported a lack of time or privacy, forgetting, or feeling tired. Women self-regulated dilator use by rotating the dilator and timing dilator use. Influencing factors were negative emotions regarding dilator use or its hard plastic design, (being anxious for) pain or blood loss, and an association with EBRT/BT. Some women mentioned a lack of instrumental support, for example, lubricants. Others received reassurance through informational support or were supported socially. ConclusionMotivation and volition processes that determined dilator use were identified and used in the development of a sexual rehabilitation intervention. It is important to provide sufficient patient information and support, and enlarge patients' perceived self-efficacy. Bakker RM, Vermeer WM, Creutzberg CL, Mens JWM, Nout RA, and ter Kuile MM. Qualitative accounts of patients' determinants of vaginal dilator use after pelvic radiotherapy. J Sex Med 2015;12:764-773.