Background. Women veterans are three to four times more likely than non-veteran women to become homeless. However, their risk factors for homelessness have not been defined. Methods. Case-control study of non-institutionalized homeless women veterans (n533) and age-matched housed women veterans (n=165). Health, health care, and factors associated with homelessness were assessed using multiple logistic regression with a Monte Carlo algorithm to estimate exact standard errors of the model coefficients and p-values. Results. Characteristics associated with homelessness were sexual assault during military service, being unemployed, being disabled, having worse overall health, and screening positive for an anxiety disorder or post-traumatic stress disorder. Protective factors were being a college graduate or married. Conclusions. Efforts to assess housed women veterans' risk factors for homelessness should be integrated into clinical care programs within and outside the Veterans Administration. Programs that work to ameliorate risk factors may prevent these women's living situations from deteriorating over time.