Introduction: The aim of the present research was to determine the effect of meta-cognitive and drug therapies on meta-cognitive beliefs of patients with obsessive-compulsive disorder.Method: The sample consisted of 60 subjects selected from patients with obsessive-compulsive disorder in Ardabil City., The subjects were randomly assigned to two experimental groups and a control group. The two techniques used were drug therapy and meta-cognitive therapy. To collect data of Psychological Interview, Meta-cognition Questionnaire and obsessive-compulsive Inventory were used in two stages. Data were analyzed using multivariate analysis of variance.Results: The results showed significant differences between therapeutic groups and control group in variables of meta-cognitive beliefs and obsessive symptoms. Multi- comparison tests revealed that meta-cognitive therapy was more effective in reducing symptoms than drug therapy. Also, meta-cognitive therapy was found to be more effective in modifying dysfunctional meta-cognitive beliefs than drug therapy.Conclusion: The results provided support for the role of meta-cognitive therapy in reducing obsessive symptoms and modifying dysfunctional meta-cognitive beliefs. .