Advance Directive (AD) is a medical agreement to ensure that patients’ autonomy is respected. In Thailand, there has been Health Act Legislation to promote the use of a living will, a form of AD, since 2007. However, there is no assessment of its practicability yet. The objective of this study was to explore perceptions and attitudes to living wills by women who were diagnosed with cancer. We conducted semi-structured interviews using a purposive sampling method. Fifteen patients at the gynaecologic oncology clinic from January 2014 to April 2015 joined the study. Participants were instructed to read the living will document designed by the Thai National Health Security Office (NHSO) and asked about 3 aspects; awareness of and attitude towards living wills, comprehension of the document, and decision-making. Final codes were analysed using investigator and data triangulation methods along with content analysis. All participants were in the early stages of cancer. Five women were diagnosed with breast cancer, 7 with cervical cancer, and 3 with ovarian cancer. None of them had heard of living wills before. Three themes emerged; 1) Participants felt overwhelmingly positive about the idea of making an AD with a living will. 2) The document was too complicated for participants. 3) Past experiences about death and terminal illness played a major role in decision-making regarding AD. In conclusion, larger scale assessment of AD in Thailand is recommended. Living wills may be useful tools for making AD in women with cancer but they need to be simplified.