Dialectical Behavioral Therapy (DBT) was initially developed and evaluated as an outpatient treatment program for borderline personality disorder (BPD). Within the last few years, several adaptations have been developed. This study aims to evaluate a three-month DBT inpatient treatment program. Clinical outcomes, including changes on measures of psychopathology and frequency of self-mutilating acts, were assessed for 50 female patients meeting criteria for BPD. Thirty-one patients had participated in a DBT inpatient program, and 19 patients had been placed on a waiting list and received treatment as usual in the community. Post-testing was conducted four months after the initial assessment. The DBT group improved significantly more than participants on the waiting list on seven of the nine variables analyzed, including depression, anxiety, interpersonal functioning, social adjustment, global psychopathology and self-mutilation. Analyses based on Jacobson's criteria for clinically relevant change indicated that 42% of those receiving DBT had clinically recovered on a general measure of psychopathology. The effect sizes ranged between moderate and strong (see fig. 1). The data suggest that three months of inpatient DBT treatment is significantly superior to non-specific outpatient treatment. Within a relatively short time frame, improvement was found across a broad range of psychopathological features. Nine and 21 month follow-up data suggest stability of the recovery.