Objective: The aim of the study was to obtain an in-depth understanding of the experience of women who received non-surgical treatment for endometrial adenocarcinoma (EAC) or endometrial hyperplasia with atypia (EHA). Enhanced understanding of women's experiences of non-surgical treatment is essential to inform counselling of the growing number of patients in this field. Methods: Individual semi-structured interviews were conducted with 21 women who received conservative (non-surgical hormonal) treatment for early stage EAC or EHA using the levonorgestrel intrauterine device (LNG-IUD) as part of the feMMe trial (NCT01686126). All interviews were audiotaped and transcribed verbatim prior to content analysis. Results: Of the 21 women interviewed, ten received conservative treatment for early stage EAC and 11 received conservative treatment for EHA. Five overarching themes were identified: i) extensive information and support needs (e.g. understanding of how the LNG-IUD treatment worked); ii) gratitude for treatment choice and non-surgical options (e.g. avoidance of potential risks associated with surgery); iii) onco-fertility (e.g. desire to maintain reproductive potential); iv) patient experience of overweight and obesity related to EAC development (e.g. history of trauma and disordered eating, multiple unsuccessful weight loss attempts); and v) patient experience of treatment options and actual non-surgical treatment (e.g. desire for early referral to counselling services). Conclusions: This qualitative investigation enabled novel insights into the treatment preferences and decision-making process of women with newly diagnosed EHA and EAC when offered non-surgical treatment options. These insights facilitate the development of pragmatic guidance and decision support tools that could be tested in future clinical trials.