Introduction In the Netherlands, assisting in suicide is allowed for physicians and regulated by the Termination of Life on Request and Assisted Suicide (review procedures) Act. However, some people decide to end their lives outside the medical domain, without a physician’s help. Two approaches for such self-directed dying are voluntary stopping eating and drinking (VSED) and independently taking lethal medication attended by a confidant (ILMC). The frequency of deaths by either of these methods in the Netherlands was examined in 2007. Since then, there have been societal, political and healthcare developments which may have had an influence on the frequency of self-directed dying. The primary objective of this study is to estimate how many people in the Netherlands currently die by VSED or ILMC. Secondary objectives include providing insight in the characteristics and quality of dying of people who choose for self-directed dying. Methods and analysis This cross-sectional study consists of an online questionnaire study (January to February 2024) among a randomly drawn sample (n=37 500) from a representative panel of the Dutch adult population in which participants are asked about potential experiences of close relatives choosing for VSED or ILMC. A two-stage screening procedure will be used to determine whether the respondents’ experiences represent a death by VSED or ILMC. Additional interviews (n=40) will be held with questionnaire respondents indicating their willingness to participate (May to September 2024). Quantitative data will be analysed using SPSS software, and qualitative data will be thematically analysed using NVivo software. Ethics and dissemination The study obtained approval from the Medical Research Ethics Committee of the Erasmus Medical Center, under number MEC-2023-0689. Informed consent will be sought from study participants in line with General Data Protection Regulation legislation. Results of the study will be disseminated through publications in scientific journals and conference ...