The purpose of the present study was to determine the prevalence rate of mental disorders in factory workers in Shahr-e-Kord and Brojen. Following a pilot study and determination of cut-off point for the SRQ-24 Questionnaire, the study was carried out in two stages. In the first stage, 503 subjects were administered the questionnaire and in the second stage, 148 subjects who had scores equal to or higher than the cut-off point were assessed by a clinical interview checklist based on DSM-IV diagnostic criteria. Results showed that the prevalence of mental disorders was 19.9% (females 23.4% and males 19.1 %). The most prevalent disorders were anxiety disorders (7.7%) and mood disorders (7%) followed by somatoform disorders (2.4%) and adjustment disorders (1.4%). The findings also indicated that the prevalence of mental disorders among technical workers, semi-skilled workers and unskilled workers were 22.6%, 20.4%, and 18.6%, respectively. There were also significant relationships between level of education, marital status and mental disorders. In this study, the prevalence of comorbid mental disorders was 26%.