This study aimed to analyze the relationships between personality disorders (PD), substance use disorder (SUD) and criminal behavior.

120 convicted offenders underwent two interviews to be evaluated for Axis I and Axis II disorders using the MINI INTERNATIONAL NEUROPSYCHIATRIC INTERVIEW – MINI 5.0 (1994, 1998, 2000, Sheehan DV & Lecrubier Y. – Brazilian Version 5.0.0) and the STRUCTURED CLINICAL INTERVIEW FOR DSM-IV AXIS II DISORDERS – SCID-II (First, Gibbon, Spitzer, Williams, & Benjamin, 1999 – Brazilian version). A random selection was made among all offenders who were serving sentences in closed conditons in two prisons with the largest population located in the State of Minas Gerais, Brazil.

Among the investigated population, Antisocial PD was the most frequent, occurring in nearly 57.7% of the sample; Dependent and Schizoid PD were uncommon. SUD were prevalent in 89.14% of the sample.

• Among the investigated population, Antisocial PD was the most frequent, occurring in nearly 57.7% of the sample;

• SUD was significantly associated with PD. It was especially significant for those with Antisocial PD, what leads to the conclusion that Antisocial PD increases the risk for SUD. This association was significant for people with Antisocial PD;

• Severe offences against life and against the person committed by the use of intentional violence were related with Antisocial PD.

• People with PD and with a history of SUD, although generally considered criminally responsible for their actions, need urgent medical and psychological care in Brazilian prisons.