Section III of the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition proposes an alternative diagnostic model for personality disorders based on the identification of pathological personality facets. Despite the existing evidence for the relationship between personality disorders and impulsivity in patients with substance use disorders, no study has yet been conducted within this framework. Thus, using a sample of 110 patients with substance use disorders, the present work aims to (a) analyze the relationship between the different personality facets and domains evaluated by the Personality Inventory for the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (PID-5) and impulsivity and (b) explore the relationships between severity of dependency and personality facets and dimensions of impulsivity. With respect to PID-5 domains, except for sensation-seeking, antagonism and disinhibition showed correlations higher than .30 with the following dimensions: urgency, premeditation, perseverance, sensation-seeking, and positive urgency (UPPS-P). The domains of detachment and psychoticism showed weaker correlations with different UPPS-P dimensions. The risk-taking PID-5 facet explains 49% variability of the sensation-seeking dimension of UPPS-P, whereas the impulsivity facet was significant on regression models computed with lack of premeditation, positive urgency, and negative urgency dimensions. Heroin and cocaine severity of dependence were moderately related to different personality facets. Lower relationships between alcohol and cannabis severity of dependence, impulsivity, and PID-5 facets were found. As a conclusion, the relationships between personality domains and impulsivity behave similarly to their five-factor equivalents for some dimensions but not for negative urgency, which might indicate the lack of specificity of this dimension of impulsivity on this type of patients.