Purpose: The primary purpose of this study was to examine the nursing practice environment and burnout of nursing personnel assigned to a deployed combat support hospital (CSH). A secondary aim was to compare differences in the level of burnout between the deployed Army nursing personnel and Army nursing personnel assigned to an Army hospital in the United States that served as the U.S. military's primary referral center for American combat casualties evacuated from Iraq. Design: A nonexperimental cross-sectional design was used for this study. Methods: The Maslach Burnout Inventory and the Practice Environment Scale were administered to 105 personnel who deployed with a CSH to Iraq. Data from this study were linked to data obtained from 152 nursing personnel who participated in an earlier burnout study at a large Army hospital in the United States. The linked datasets yielded a final sample of 257 Army nursing personnel. Analysis of variance and linear regression analysis were used to analyze these data. Findings: Emotional exhaustion was common across groups. For the deployed nursing personnel, emotional exhaustion was related to a perceived lack of support from management, foundations for quality of care, collegial relationships, and extended work schedules. The U.S.-based Army hospital group scored significantly higher emotional exhaustion, but it was related to the additional responsibilities associated with being an Army nurse, working extended schedules, and working with combat casualties for extended periods of time. The U.S.-based group perceived more personal accomplishment from the work they do. Conclusions: Burnout was common across Army hospital settings. Emotional exhaustion was most problematic in the U.S.-based Army hospital; however, there was less cynicism toward patients and a greater perception of personal accomplishment associated with work. Clinical Relevance: This study supports the importance of a professional practice environment for Army nursing personnel both during deployment and in U.S.-based Army hospitals. © 2012.