This paper explores the personality disorders most commonly related to cocaine addiction. The samples used were 60 cocaine-addicted patients, who were assessed with the MCMI-II before treatment, and 50 normative participants from the general population with the same demographic features (age, sex and socioeconomic level). According to the results, 36.7% of the clinical sample (versus 16% of the normative sample) showed at least one personality disorder. The most prevalent disorders in the cocaine sample were Passive-Aggressive Personality Disorder and Dependent Personality Disorder (10% in each case), followed by Obsessive-Compulsive Personality Disorder and Histrionic Personality Disorder (6.7% each). Moreover, 15% of the clinical sample showed more than one personality disorder. Finally, the implications of this study for clinical practice and future research in this field are discussed.