Patients with borderline personality disorder (BPD) are known to use nonsuicidal self-injury (NSSI) as a dysfunctional strategy to regulate intense emotions. The primary purpose of this study was to clarify the motives for NSSI along with their interrelations. We further investigated the variety of emotions preceding NSSI and possible effects of NSSI on these emotions. To this end, a structured self-rating questionnaire on NSSI was administered to 101 female BPD-patients exhibiting NSSI. Most patients reported multiple motives for NSSI. The motives were more likely to compound than to exclude one another. Negative reinforcement was almost always involved in NSSI, whereas positive reinforcement (e.g., “getting a kick”) played an additional role among about half of the patients. NSSI was usually preceded by a large variety of negative feelings that were reported to clearly improve with NSSI. In conclusion, therapists should anticipate a multidimensional functional spectrum when exploring motives of NSSI.