While the existing research consistently points to the effectiveness of Dialectical Behavior Therapy (DBT) in treating borderline personality disorder, little qualitative research has been conducted to ascertain the reasons for its success, especially from the perspective of those undergoing the treatment. Our qualitative investigation was undertaken with the goal of understanding, from the perspective of the client, what is effective about DBT and why. We interviewed 14 clients who were involved in a DBT program run by Assertive Community Treatment (ACT) of Kalamazoo, Inc. All of the women interviewed reported that DBT had a positive impact on their lives.