Resumen: In this study, the impact of religion on the ethical values of Spanish ecologists in relation to the environment was analysed, based on an online survey and a work seminar in which representatives of the main environmental NGOs in Spain participated. The religious affiliations of the respondents were found to be significantly different compared to those of Spanish society, with a much higher proportion of Buddhists, agnostics, and atheists, and a smaller proportion of Catholics. The environmental values of the NGO members did not show significant differences according to the religious group, which implies that religious beliefs do not affect ethical values related to the environment. However, religion did have a significant influence on activists' views on other bioethical issues. Catholics and believers of other religions were found to be more in favour than agnostics and atheists of introducing ethical limits on abortion, euthanasia, or the manipulation of human embryos.