There has been considerable interest in computer viruses since they first appeared in 1981, and especially in the past few years as they have reached epidemic numbers in many personal computer environments. Viruses have been written about as a security problem, as a social problem, and as a possible means of performing useful tasks in a distributed computing environment. However, only recently have some scientists begun to ask if computer viruses are not a form of artificial life—a self-replicating organism. Simply because computer viruses do not exist as organic molecules may not be sufficient reason to dismiss the classification of this form of “vandalware” as a form of life. This paper begins with a description of how computer viruses operate and their history, and of the various ways computer viruses are structured. It then examines how viruses meet properties associated with life as defined by some researchers in the area of artificial life and self-organizing systems. The paper concludes with some comments directed toward the definition of artificially “alive” systems and experimentation.