Anxiety and related disorders are among the most common mental disorders, but are under-diagnosed and under-treated. They are : very common in clinical practice, and frequently comorbid with other psychiatric and medical conditions. Optimal management requires a good understanding of the efficacy and side effect profiles of pharmacological and psychological treatments.   These guidelines were developed by Canadian experts in anxiety and related disorders through a consensus process. They are presented in 10 sections, including an introduction, principles of diagnosis and management;  six sections (3-8) on the specific anxiety-related disorders (panic disorder, agoraphobia, specific phobia, social anxiety disorder, generalised anxiety disorder, obsessive-compulsive disorder, and posttraumatic stress disorder); and two additional sections on special populations (children/adolescents, pregnant/lactating women, and the elderly) and clinical issues in patients with comorbid conditions.