Aim: To explore the significance of culture, professional support in the community, social interactions and intrapersonal determinants of adults' preferences for life-sustaining treatments and palliative care. Methods: A cross-sectional design with a Social Ecological Model was used. Between 1 October 2012 and 31 December 2012, 474 adults aged ≥20 years living in a city of Southern Taiwan completed the survey. Data were analysed using hierarchical multiple regression. Results: The life-sustaining measures model was significant with 15.3% (p < 0.0001) of the variance in the Modified Emmanuel Medical Directives being explained by variables of death of self and healthcare services' support. The palliative care model was significant with 18% (p < 0.0001) of the variance in the Modified Hospice Attitude Scale being explained by variables of palliative care knowledge, death of self and social interactions. However, cultural value adherence did not predict adults' preferences for life-sustaining measures and community resources support did not predict palliative care preference. Conclusions: Findings enhance our understanding of the significance of different societal levels on adults' preferences for end-of-life care. Palliative care knowledge, fear of death, healthcare services' support and social interactions are essential factors that need to be taken into consideration when it comes to discussion about life-sustaining treatments and palliative care. Summary statement: What is already known about this topic?. End-of-life (EOL) preferences can be shaped not just by knowledge, values and individuals' attitudes but rather a host of social influences. Few studies with theoretical frameworks or models in the literature are available to provide a comprehensive understanding of factors contributing to responses at the EOL. What this paper adds?. The findings advance the knowledge of the influence of social interactions, healthcare services' support, palliative care understanding and fear of death on adults' preferences for life-sustaining treatments and palliative care. The identified relationships in the context of life-sustaining treatments and palliative care provide practical guidelines, which can help to inform appropriate supportive interventions for EOL care planning. The implications of this paper:. Healthcare services that provide a mediating structure where a person belongs should focus on enhancing community resources regarding EOL healthcare planning, knowledge about palliative care and reinforcing life and death education. The social support network and emotional ties with a person's significant others should also be taken into consideration to facilitate EOL healthcare planning and to promote good quality of life at EOL.