In order to identify the mental state of prisoners, the present study examines factors associated with mental health of prison inmates is Ilam. Required information was collected through a questionnaire which was distributed among 343 prisoners who were selected by quota sampling method.Research findings indicate that the mean of mental health scores for subjects is. 83.17, which is below the appropriate level of mental health.. mental health variable was divided into its constituent components, namely, physical (mean score 20.65), anxiety (mean score 21.71), depression (mean score 20.79) and social functioning (mean score 20.11). Also, based on research resultsthere is significant relationships between variables such as amount of social capital (r=0.134), religious orientation (r =0.102), sentence length (r=-0.18), amount of aggression (r= -0.38), social alienation (r= -0.28), duration of detention (r=0.15), rate of relative deprivation (r=0.15)and coping with stress (r=0.223) with dependent variable (mental health).. Regression analysis showed that variables of alienation , relative deprivation, aggression, and social capital, are respectively impoerant in explaining the dependent variable. Overlal, they explain52% of the variance of the dependent variable.