Comorbid diagnoses were examined in 55 principal generalized anxiety disorder (GAD) clients, and the effect of treatment for the principal disorder on those conditions was evaluated. High rates of comorbid diagnoses were present at pretherapy, with social and simple phobia being most common. The presence of additional diagnoses declined dramatically from pretherapy to follow-up and was significantly greater among clients for whom the GAD therapy had been successful than among clients for whom GAD outcome had been ambiguous. This was generally true regardless of whether clients reported at follow-up that they had received further therapy since the posttherapy assessment.