Background: Various studies have been conducted to determine the causes of drug abuse from a psychological perspective. Mental health has also been among the studied factors. The present study aimed to investigate the relationship between mental health and general self-efficacy beliefs, coping strategies and locus of control in male drug abusers.Methods: This was a correlational descriptive study involving all male drug abusers (4,493 cases) at self-introducing detoxification centers in Kerman during 2010-11. A total number of 354 patients were selected randomly with cluster sampling. Measurement tools were included Goldberg’s General Health Questionnaire (GHQ-28), Generalized Self-Efficacy Scale (GSE-10), Coping Responses Inventory (CSI), and Internal–External Locus of Control Scale (I-E). The survey data were analyzed by SPSS using Pearson correlation and stepwise regression.Findings: The results of data analyses showed significant correlations between mental health and self-efficacy beliefs (r = -0.626), problem-oriented coping strategy (r = -0.535), emotion-oriented coping strategy (r = 0.573), external locus of control (r = -0.298), and internal locus of control (r = -0.525) (P < 0.01 for all). The results of the regression analysis showed that 58.7 percent of total variance of mental health can be estimated by general self-efficacy beliefs, coping strategies and locus of control.Conclusion: In general, the results showed that increased levels of general self-efficacy, problem-oriented coping strategy and internal locus of control will improve mental health. In contrast, decreased general self-efficacy, emotion-oriented coping strategy and external locus of control would lead to decreased mental health.Keywords: General self-efficacy beliefs, Coping strategies, Locus of control, Mental health, Substance abusers.