The aim of the present review was to provide an updated investigation of literature from the past ten years that examined the effects of comorbid problems on treatment outcomes, and/or explored if cognitive behavioral treatments (CBT) targeting anxiety disorders also affected comorbid disorders. A search of the literature resulted in a total of 33 publications, based on 28 randomized controlled trials that met predefined inclusion criteria. An analysis of studies that examined whether comorbidity affects treatment outcome yielded mixed results for different types of comorbidities. The inconsistent results were largely due to methodological heterogeneity in the identified studies. Support for negative effects of comorbidity on treatment outcomes was usually found in studies that investigated comorbidity as a categorical diagnosis, rather than symptom levels, and those that analyzed specific comorbid diagnoses, rather than grouping them together. Overall, our findings suggest that comorbid disorders may have a more negative impact on treatment outcomes than proposed in previous reviews, particularly in the cases of comorbid social anxiety and mood disorders. Furthermore, CBT for anxiety disorders in children was found to ameliorate comorbid problems.