Results are presented for the largest study (N = 53,692) ever conducted on the 25-item Connor-Davidson Resilience Scale (CD-RISC), a popular measure of resilience. We examined the internal consistency of the CD-RISC items and associated mean resilience levels within a sample of enlisted basic trainees in the United States Air Force. In addition, the predictive validity of the CD-RISC Total Score was examined for real-life military outcomes, including attrition from service and mental health diagnosis. The CD-RISC items demonstrated strong internal consistency. Item-level examinations of scores revealed that most trainees reported relatively high resilience. Results indicated that resilience measured at the beginning of military service is a significant predictor of (a) attrition from service and (b) obtaining a mental health diagnosis within 6 months of entry. Implications and future directions are discussed.