A significant proportion of individuals suffering from posttraumatic stress disorder do not seek or receive effective treatment. Understanding the reasons why an individual chooses to seek treatment or prefers one treatment to another is a critical step to improve treatment seeking. To begin to understand these reasons, we conducted a qualitative analysis of the reasons women gave for choosing a cognitive-behavioral treatment, prolonged exposure (PE), or a pharmacological treatment, sertraline (SER). A community sample of women with trauma histories were asked to view standardized rationales, to choose among PE, SER, or no treatment, and to give 5 reasons for their choice. Women indicated that they were more likely to prefer the psychotherapy to the medication. Across reasons given, the most commonly cited reason for treatment preference highlighted why or how the treatment worked (e.g., I need to talk about it); and this reason emerged as the strongest predictor of preference for PE. Understanding this role of perceived treatment mechanism may aid clinicians and public health policy officials to identify and address help-seeking barriers regarding treatment.