Objective: This study aimed to determine factors associated with hospitalization and decisions to prescribe psychotropic medication for patients with borderline personality disorder seeking care at psychiatric emergency units. Methods: A total of 11,578 consecutive visits were reviewed over a four-year period at a psychiatric emergency service in a tertiary hospital in Spain. Some patients were repeat visitors. Data collected included sociodemographic, clinical, social, and therapeutic information and the Severity of Psychiatric Illness (SPI) score. Results: Borderline personality disorder was the diagnosis in 1,032 of the visits (9%) to the emergency department, which corresponded to 540 individuals. Of these visits, 11% required hospitalization. Multivariate statistical logistic regression analysis showed that the decision to hospitalize was associated with risk of suicide, danger to others, severity of symptoms, difficulty with self-care, and noncompliance with treatment. The decision to prescribe benzodiazepines was related to male sex, anxiety as the reason for seeking care, little difficulty with self-care, few medical or drug problems, and housing instability. Factors related to the prescription of antipsychotics were male sex, risk of endangering others, and psychosis as the reason for the visit. Factors associated with the prescription of antidepressants were depression as the reason for seeking help and little premorbid dysfunction. Conclusions: Patients with borderline personality disorder had greater clinical severity, but the percentage of hospitalizations was lower than for patients without the disorder. Although a psychiatric emergency service is not the ideal setting to initiate pharmacotherapy, in practice, psychiatrists often prescribe medications in this setting. The SPI was a good tool to assess the severity of illness of these patients.