OBJECTIVE: Posttraumatic Stress Disorder (PTSD) and childhood abuse are both consistently associated with a higher risk for suicide attempts. We hypothesize that among patients reporting childhood abuse, PTSD diagnoses are correlated with an increased severity of suicidal features. METHOD: We investigated 726 adult patients who had attempted suicide. These participants were assessed on lifetime clinical diagnoses and childhood abuse. The association of PTSD and childhood abuse dimensions with age at first suicide attempt, number of suicide attempts, violent attempts, serious attempts and suicide intent was studied. An adjusted multinomial logistic regression was performed to ascertain if childhood abuse and PTSD increased the severity of the suicidal behavior when combined. RESULTS: Several types of childhood abuse (emotional, physical and sexual abuse) when combined with a lifetime diagnosis of PTSD showed an increased risk for more suicide attempts, serious attempts, and a higher level of suicidal intent compared with the absence of any or both risk factors. CONCLUSION: The combination of PTSD and childhood abuse should be investigated in clinical settings due to an augmented risk for more severe suicidal behavior.