Chronic urticaria is a common disorder which can be extremely distressing and disabling for the patients. Anamnesis and clinical investigations are very helpful for the diagnosis. Bacterial, viral or parasitic infections can be associated with chronic urticaria, although the mechanisms which may link infectious diseases and chronic urticaria remain unclear. Recently, direct relationship between chronic urticaria and Helicobacter pylori, hepatitis C virus and Toxocara canis infections have been postulated. Numerous studies have also shown that chronic urticaria and angiodema are significantly associated with thyroid autoimmunity. A connective tissue disorder should be investigated if skin biopsy shows histologic evidences of vasculitis or if the patient has signs of systemic disease. Despite extensive laboratory investigations, 60 to 80% of chronic urticaria remain idiopathic. Large clinical studies have shown that extensive screening is unnecessary. Second-generation, low-sedation H1-antihistamines are the treatment of choice in chronic idiopathic urticaria. Combined therapies with first and second-generation H1-antihistamines or with H1 and H2-antihistamines have been proposed and found to be effective. Systemic corticoids and immunosuppressive agents should be reserved for patients with severe and disabling chronic urticaria but they cause undesirable effects and toxicity.