Introduction: In recent years there has been an increase in the number of young people in prison. This
study is the first to look at the proportion of psychiatric disorders among young adult prisoners. Objective: The main objective is to determine the percentage of psychiatric disorders among young adult male prisoners Method: A cross sectional study of young adult male prisoners, with ages ranged between 18 and 21 years old, was conducted between September and December, 2008 at the Kajang Prison. A total of 225 inmates participated in the study which used the Mini International Neuropsychiatric Interview (M.I.N.I) as its instrument. Results: The percentage of psychiatric disorders was 60.0%. Alcohol and substance related disorders had the highest prevalence at 50.2%, followed by Major Depressive Disorders and Dysthymia at 16.9%. About 39.6% were observed to have antisocial personality disorder. Psychiatric disorders were found to have significant differences (p