This study of 315 male and 310 female homeless military veterans in a V.A. inpatient program designed to treat substance abusers, many of whom also suffer psychiatric disorders, was designed to examine gender differences in factors associated with the odds of having suicidal thoughts, and of attempting suicide, in comparison to being nonsuicidal. A maximum likelihood estimation multinomial logistic regression showed childhood and current sexual and physical abuses, depression, fearfulness, relationship problems, limited social support, and low self-esteem was more strongly associated with suicidal thoughts and attempts for women than for men veterans. Extent of alcohol and other drug abuse, aggression, resilience, self-efficacy, combat exposure, combat-related PTSD, and work problems were more strongly associated with suicidal thoughts and attempts for men than for women. Implications of these findings for V.A. programs are discussed.