The primary objective of this study was to describe the development, reliability, and construct validity of scores on the Military to Civilian Questionnaire (M2C-Q), a 16-item self-report measure of postdeployment community reintegration difficulty. We surveyed a national, stratified sample of 1,226 Iraq and Afghanistan veterans who used U.S. Department of Veterans Affairs (VA) medical care; 745 completed the M2C-Q and validated mental health screening measures. All analyses were based on weighted estimates. The internal consistency of the M2C-Q was .95 in this sample. Factor analyses indicated a single total score was the best-fitting model. Total scores were associated with measures theoretically related to reintegration difficulties including perception of overall difficulty readjusting back into civilian life (R 2 = .49), probable PTSD (d = 1.07), probable problem drug or alcohol use (d = 0.34), and overall mental health (r = -.83). Subgroup analyses revealed a similar pattern of findings in those who screened negative for PTSD. Nonwhite and unemployed veterans reported greater community reintegration difficulty (d = 0.20 and 0.45, respectively). Findings offer preliminary support for the reliability and construct validity of M2C-Q scores. Published 2011. This article is a US Government work and is in the public domain in the USA..