The aim of this thesis is to examine process theology in the light of questions raised by environmental issues. To facilitate this study, different approaches to the nonhuman natural world developed in environmental philosophy - in particular in environmental ethics - are compared with the work of process theologians. The primary focus is on the systems of A.N.Whitehead and Charles Hartshorne, but John Cobb, Jay McDaniel and Daniel Dombrowski are also considered. In Chapter 1, the derivation of value and the formation of ethics in process thinking is examined, and its ethical methodology and content compared with classical utilitarianism and more recent consequentialist approaches to the nonhuman natural world. Ensuing problems including justice, replaceability, the identification of value with experience and the subjectivity of value judgments are considered. In Chapter 2, process ethics is compared with deontological approaches to environmental ethics which focus on the value of individual organisms and natural objects: in particular, the work of Paul Taylor. Problems generated by egalitarianism, individualism and the inability to affirm environmental restitution are examined. The capacity of process thinking to resist such criticisms is assessed. Collective consequentialist ethical approaches to the environment, characterized by Aldo Leopold and J.Baird Callicott, are laid alongside process ethics in Chapter 3. This raises questions concerning the nature of species and ecosystems, and the use of metaphors such as organism, community and society to describe them. The focus moves in Chapter 4 onto a comparison of the metaphysics and ethics of the Deep Ecology movement with that of process theology. This comparison concentrates on two main themes: attitudes to 'holism' and to the 'extension and realization of the self'. Finally, the question whether process theology should reform itself as a better response to environmental ethics is examined. Some suggestions about possible reformation are proffered, but it is tentatively concluded that process thinking is an inappropriate basis for environmental philosophy.