Posttraumatic stress disorder (PTSD) occurs in an estimated 8% of men and 20% of women who are exposed to traumatic events. PTSD is a trauma- and stress-related disorder associated with significant psychosocial morbidity, substance abuse, and other negative physical health outcomes. The hallmarks of PTSD include exposure to a traumatic event; reexperiencing the event or intrusion symptoms; avoidance of people, places, or things that serve as a reminder of the trauma; negative mood and thoughts associated with the trauma; and chronic hyperarousal symptoms. Self-report questionnaires can assist clinicians in identifying anxiety problems associated with traumatic events. For patients who meet criteria for PTSD, trauma-focused psychotherapy and pharmacotherapy improve symptoms. Benzodiazepines and atypical antipsychotics are not recommended because studies have shown that adverse effects outweigh potential health benefits. Primary care physicians should monitor patients with PTSD for comorbid conditions such as substance abuse, mood disorders, and suicidality, and should refer patients to behavioral health specialists and support groups when appropriate.