Two open trials of Virtual Reality based exposure therapy (VRE) to desensitize Vietnam veterans with Posttraumatic Stress Disorder (PTSD) to some of their traumatic memories are described. A total of 21 patients were exposed to one of two virtual Vietnam computer-generated environments in which their individual traumatic experiences were simulated in response to their recounting these events. Although two patients experienced significant increases in symptoms during VRE, all patients’ PTSD symptoms were below baseline by the 3-month posttreatment assessment. When the data from the two open trials was combined, clinically meaningful and statistically significant reductions in PTSD symptoms were found. These changes were long lasting as evidenced by the 6-month follow-up assessments. Two case examples are provided and future applications of this treatment are discussed. [Article copies available for a fee from The Haworth Document Delivery Service: 1-800-HAWORTH. E-mail address: <docdelivery@haworthpress.com> Website: <http://www.HaworthPress.com> © 2006 by The Haworth Press, Inc. All rights reserved.].