High rates of comorbid depression and anxiety often complicate psychological interventions. The current preliminary study was designed to examine the efficacy of a unified and transdiagnostic model based on emotion regulation skills for patients with comorbid depression and anxiety. Forty-three participants with a diagnosis of major depression and varying levels of comorbid anxiety symptoms were randomly assigned to either a unified and transdiagnostic treatment group (UP; n= 20) or a wait-list control group (n= 23). The treatment group received 14 weekly UP sessions. Scores on the Beck Depression Inventory-II, Beck Anxiety Inventory, and Emotion Regulation Questionnaire were used as outcome measures. Data provided preliminary evidence that UP can be effective in reducing depressive and anxiety symptoms and in improving the use of effective emotion regulation strategies up to 3 months. Present results support the implementation of UP as a beneficial group treatment for patients with comorbid depressive and anxiety symptoms.