A substantial proportion of Borderline Personality Disorder (BPD) patients respond by a marked decrease of psychopathology when treated with Dialectical Behavioral Therapy (DBT). To further enhance the rate of DBT-response, it is useful to identify characteristics related to unsatisfactory response. As DBT relies on emotional learning, we explored whether dissociation-which is known to interfere with learning- predicts poor response to DBT. Fifty-seven Borderline Personality Disorder (BPD) patients (DSM-IV) were prospectively observed during a three-month inpatient DBT program. Pre-post improvements in general psychopathology (SCL-90-R) were predicted from baseline scores of the Dissociative Experiences Scale (DES) by regression models accounting for baseline psychopathology. High DES-scores were related to poor pre-post improvement (β = -0.017 ± 0.006, p = 0.008). The data yielded no evidence that some facets of dissociation are more important in predicting DBT-response than others. The results suggest that dissociation in borderline-patients should be closely monitored and targeted during DBT. At this stage, research on treatment of dissociation (e.g., specific skills training) is warranted.