Drawing on 26 months of field research in El Salvador during the civil war, I analyze some ethical challenges that confront field researchers working in conflict zones. After briefly summarizing the purpose and general methodology of my research, I discuss in detail the research procedures I followed to implement the “do no harm” ethic of empirical research. I first analyze the particular conditions of the Salvadoran civil war during the period of research. I then discuss the procedures meant to ensure that my interviews with people took place with their fully informed consent—what I understood that to mean and how I implemented it. I then turn to the procedures whereby the anonymity of those interviewed and the confidentiality of the data gathered were ensured to the extent possible. Throughout I discuss particular ethical dilemmas that I confronted, including issues of self-presentation and mistaken identity, the emotional challenges of field work in highly polarized settings (which if not well understood may lead to lapse in judgment), and my evolving questions concerning the researcher role and its limitations. I also discuss the dilemmas that arise in the dissemination of research findings and the repatriation of data.