Mixed symptoms of anxiety and depression are highly prevalent among patients with psychic complaints. The number and duration of symptoms and the degree of impairment determines whether the condition fulfils the criteria for an anxiety and depressive disorder. Increasing attention is now being given to the clinical significance of subsyndromal anxiety and depression because of the functional impairment inflicted. Epidemiological studies and clinical experience show that comorbidity of anxiety and depressive disorders is highly prevalent. This may partly be attributed to common genetic causes; partly to environmental causes. Concurrent anxiety and depression pose a challenge in term of differential diagnoses. The treatment of such co-morbid disorders also calls for some special precautions.