Background: French Guiana has the highest incarceration rate among French territories, it is higher than that of Brazil, Colombia or Venezuela. It is well known that mental health problems are over-represented in correctional facilities. Our objectives were to describe the prevalence of various psychiatric conditions and to study factors associated with violence and repeated offenses among arriving detainees at the sole correctional facility of French Guiana. Methods: The study was cross-sectional. All consenting new adult prisoners incarcerated between 18/09/2013 and 31/12/2014 at the penitentiary centre of French Guiana were included. The Mini International Neuropsychiatric Interview (MINI) was used to screen for psychiatric diagnoses. In addition sociodemographic data was collected. Results: Overall 647 men and 60 women were included. The participation rate was 90%.Overall 72% of patients had at least one psychiatric diagnosis (Fig. 2). Twenty percent had three or more diagnoses. Violent index offences were not more frequent among those with a psychiatric diagnosis (crude odds ratio 1.3 (95%CI = 0.9–2), P = 0.11. Multivariate analysis showed that after adjusting for sex and age, psychosis, suicidality and post-traumatic stress disorder were independently associated with violent offences. Generalized anxiety disorder was less likely to be associated with incarceration for violent offences. Having a history of a previous incarceration was significantly associated with a psychiatric condition in general (any diagnosis) OR = 3 (95%CI = 2–4.3), P < 0.0001. Calculations of the population attributable risks showed that in the sample 31.4% of repeat incarcerations were attributable to antisocial personality disorder, 28.3% to substance addiction, 17.3% to alcohol addiction, 8.7% to depression and 7% to psychosis.