Background: Due to the nature of their job military personnel is highly mobile and posted away from their family for extended period of time. As result personnel who are on active military service may be exposed to undesirable sexual behaviors. OBJECTIVES: The objective of this study was to assess the relationship between duty location and sexual behavior of married military personnel. METHODS: This is a comparative cross-sectional study conducted among military personnel in Tigray. Data were collected using self administered questionnaire and FGD from married military personnel RESULTS: Military personnel stationed away from their spouses were more likely to have extra-marital sex than those who were living together with their spouses, adjusted odds ratio is 2.14(1.40, 3.27) Conclusion: Military personnel posted away from their spouse are likely to be engaged in sexually risk behaviors thus appropriate sexual health package including condom promotion and regulation of commercial sex industry need to be strengthened