Levocetirizine has been shown in observational studies in the west as an effective and satisfactory therapy for patients with allergic respiratory and skin disease. An open-label, multicentre observational study to investigate the patients’ perception of levocetirizine in the treatment of allergic rhinitis (AR) and urticaria in Taiwanese patients. Three hundred and thirty-three patients (236 AR and 97 urticaria patients) attending out-patient clinics of medical centres across Taiwan. Patients were treated with levocetirizine 5mg once daily (AR patients for 2-4 weeks and urticaria patients for 2-6 weeks) and at the end of treatment evaluated for symptoms of disease, perception of change in symptoms, global efficacy and tolerability, global preference over previous antiallergic treatment, change in quality of sleep/daily activities, and safety and adverse events (AEs). Levocetirizine markedly improved the symptoms of AR and urticaria; with 70%-75% of AR patients and 60%-80% of urticaria patients reporting complete or marked improvements in individual symptoms. Asthma symptoms were completely or markedly improved in 44% of patients with AR and concomitant asthma. The majority of patients were satisfied with levocetirizine therapy and 50%-70% indicated preference for levocetirizine over previous therapy. Overall, 50%-74% of all patients perceived improvements in quality of sleep/daily activities and 50%-65% of the patients rated the onset of action for levocetirizine as very rapid or rapid. Somnolence was the most common AE, reported by 7.4% of AR and 7.0% of urticaria patients. The results of this study indicated Levocetirizine is an effective and satisfactory therapy for the management of allergic respiratory and skin disease in Taiwanese subjects.