Social Anxiety Disorder is a common disorder leading functional impairment. The comorbidity between mood disorders with social anxiety disorder is relatively common. This comorbidity impacts the clinical severity, resistance and functionality of patients. The systematic evaluation of the comorbidity in both patient groups should not be ignored and be carefully conducted. In general, social anxiety disorder starts at an earlier age than mood disorders and is reported to be predictor for subsequent major depression. The absence of comorbidity in patients with social anxiety disorder is a predictor of good response to treatment. In bipolar disorder patients with comorbid social anxiety disorder, there is an increased level of general psychopathology. Besides, they have poor outcome and increased risk of suicide. In this article, comorbidity between these two disorders has been evaluated in detail.