This article serves as an introduction to an examination of how Christian and Buddhist ethics have influenced the depiction of immortality in Doctor Who. Both Christianity and Buddhism could be said to have clearly defined stances regarding immortality—simply put, both generally regard the human pursuit of eternal life as reprehensible, albeit for somewhat different reasons. During its run, Doctor Who has tackled a variety of ethical issues, the problematic aspects of immortality being a recurring theme. As an overview of selected Doctor Who episodes illustrates, the series tends to agree on viewing immortality as ethically questionable, and furthermore, to reflect the views of both Christianity and Buddhism in how it communicates its own approach. Whether the emphasis is on Christian or Buddhist ideas (such as an authoritative concept of law or the essential nature of life as suffering, respectively) varies from one story to another, but it appears that both have played, and continue to play, an integral part in how narratives regarding immortality are shaped and dealt with in the series. The findings from Doctor Who suggest that the series is a fruitful source in terms of examining the role of religious influences in the discussion regarding ethical dilemmas.