This article provides an overview of the use of the Internet for conducting studies after terrorist attacks and other large-scale disasters. We begin with a brief summary of the scientific and logistical challenges of conducting such research, followed by a description of some of the most important design features that are required to produce valid findings. We then describe one approach to Internet surveys that, although not perfect, addresses many of the challenges well. We close with some thoughts about how the Internet-based methods available today are likely to develop further in coming years.