Objectives: Facilitated advance care planning (ACP) helps family carers' to be aware of patient preferences. It can improve family carers' involvement in decision making and their overall experiences at the end of life, as well as, reduce psychological stress. We investigated the effects of the ACTION Respecting Choices (RC) ACP intervention on the family carers' involvement in decision making in the last 3 months of the patients' life and on the family carers' psychological distress after 3 months of bereavement. Methods: Over six European countries, a sample of 162 bereaved family carers returned a bereavement questionnaire. Involvement in decision making was measured with a single item of the Views of Informal Carers-Evaluation of Services Short Form questionnaire. Psychological distress was measured with the Impact of Event Scale (IES). Results: No significant effect was found on family carers involvement in decision making in the last 3 months of the patients' life (95% CI 0.449 to 4.097). However, the probability of involvement in decision making was slightly higher in the intervention arm of the study (89.6% vs 86.7%; OR=1.357). Overall, no statistical difference was found between intervention and control group regarding the IES (M=34.1 (1.7) vs 31.8 (1.5); (95% CI -2.2 to 6.8)). Conclusion: The ACTION RC ACP intervention showed no significant effect on family carers' involvement in decision making or on subsequent psychological distress. More research is needed about (1) how family carers can be actively involved in ACP-conversations and (2) how to prepare family carers on their role in decision making. Trial registration number: International Standard Randomised Controlled Trial Number ISRCTN17231.