Objective: Intimate partner violence (IPV) is a serious health concern, but little is known about prevalence of IPV in the armed forces, as military members cope with the pressures of long-standing operations. Furthermore, previous prevalence studies have been plagued by definitional issues; most studies have focused on acts of aggression without consideration of impact (clinically significant [CS] IPV). This is the first large-scale study to examine prevalences of IPV, CS-IPV, and clinically significant emotional abuse (CS-EA) for men and women. Method: A United States Air Force-wide anonymous survey was administered across 82 bases in 2006 (N = 42,744) to assess IPV, CS-IPV, and CS-EA. Results: The adjusted prevalence of CS-IPV perpetration was 4.66% for men and 3.54% for women. Prevalences of IPV perpetration were 12.90% for men and 15.14% for women. CS-EA victimization was 6.00% for men and 8.50% for women. Sociodemographic differences in risk for violence were found for gender, race/ethnicity, pay grade, religious faith, marital status, and career type even after controlling for other demographic variables. Conclusions: Partner maltreatment is widespread in military (and civilian) samples. Men were more likely to perpetrate CS-IPV, whereas women were more likely to perpetrate IPV. Specific demographic risk factors were identified for different types of partner maltreatment (e.g., lower rank predicted higher risk for both perpetration and victimization across men and women). Other sociodemographic differences varied across severity (IPV vs. CS-IPV) and across gender. (Contains 5 tables.)