Prior research has pointed to an association between a history of traumatic events and premenstrual syndrome (PMS) in women. The objective of this study was to further investigate the relationship between trauma and PMS among female veterans, a population with high rates of sexual and physical abuse, as well as combat-related exposures. We conducted a case-control study of 502 women veterans under the age of 52 who were associated with the Iowa City Veterans Affairs Medical Center. Trauma history, gynecological health, mental health (including posttraumatic stress disorder), and other variables were obtained through telephone interview. Cases were women who had moderate to severe PMS as defined by validated criteria and controls were women without PMS. The prevalence of PMS was 14.3%. Thirty-three percent of subjects reported a completed sexual assault, 29% a combat-related trauma, and 86% a non-combat related trauma. Factors significantly associated with PMS (p<0.05) in the univariate analysis were: attempted, completed, and number of rapes during a woman's lifetime; rape before age 18; rape during military service; childhood sexual abuse; and number of non-combat related traumas. Childhood physical abuse and combat-related trauma were not associated with PMS in univariate analyses. In our final multivariate model, lifetime completed sexual assault was associated with PMS (odds ratio =2.42, 95% confidence interval = 1.33-4.40). Findings from this study among female veterans indicate that a history of trauma, particularly sexual trauma, is associated with moderate to severe PMS. Further study is warranted to confirm temporal relationships and causal mechanisms.