. Bipolar disorder (BD) is associated with a significant burden due to affective symptoms and behavioral manifestations, but also cognitive and functional impairment. Comorbidity with other psychiatric conditions, including personality disorders, is frequent. The comorbidity with psychopathy deserves special consideration given that both disorders share some clinical characteristics, such as grandiosity, risky behavior or poor insight, among others, that can worsen the outcome of BD. Therefore, this study aimed to evaluate the prevalence of psychopathy in a sample of clinically stabilized patients with BD and its impact on the severity of BD. . A sample of 111 patients with BD (38 type I and 73 type II) was studied. The Hamilton Depression Rating Scale (HAM-D) and the Young Mania Rating Scale (YMRS) served to assess the severity of BD. Psychopathy was measured by means of the Psychopathic Personality Inventory-Revised (PPI-R). Patients were divided into three groups according to the severity of psychopathy (Group 1: no psychopathy; Group 2: “psychopathic” trait; Group 3: clinical psychopathy). Other measures regarded impulsiveness (Barratt Impulsiveness Scale-11, BIS-11) and empathy (Empathy Quotient, EQ). Comparisons of mania, depression, impulsivity and empathy scores were run with MANOVA considering psychopathy and diagnosis as independent variables. . The prevalence of psychopathy was 5.4%. A significant association between the level of psychopathy and YMRS, attentional/cognitive impulsivity and motor impulsivity scores emerged. No interaction between psychopathy and BD diagnosis was found. Post hoc analysis demonstrated significantly higher YMRS scores in Group 3 than in Group 1; that is, patients with psychopathy have more manic symptoms. . Psychopathy seems quite frequent among patients with BD. The association of psychopathy with BD results in higher impulsivity and manic symptoms. In light of this, psychopathy should be investigated when assessing patients with BD, regardless of the comorbidity of BD with other personality disorders.