Allergic rhinitis (AR) is a major health problem that can significantly impair quality of life (QoL). The former classification of AR comprises seasonal allergic rhinitis (SAR) and perennial allergic rhinitis (PAR), which do not adequately reflect the clinical course and presentation of AR. The Allergic Rhinitis and its Impact on Asthma (ARIA) classification is based on the duration of symptoms and their severity. Persistent AR (PER) is experienced for periods longer than 4 days/week and for more than 4 consecutive weeks, and may feature mild or moderate-to-severe disease based on the impairment of QoL and symptom severity. Oral antihistamines are a standard treatment option in AR. New second generation antihistamines have a rapid onset of action, are highly effective on AR symptoms, and some were even shown to relieve nasal congestion. Levocetirizine is a potent histamine H 1-receptor antagonist with proven efficacy in both SAR and PAR, and it is the best studied therapeutic option in persistent AR. The Xyzal in Persistent Rhinitis Trial (XPERT™) studied 551 patients with PER, showing that levocetirizine (5 mg/day compared with placebo) significantly improved nasal symptoms as early as the first week and for the 6 months of study, with significant improvement in nasal congestion after 6 weeks of treatment. Levocetirizine also improved QoL, was well tolerated, and produced substantial societal and employer cost savings. Thus, levocetirizine is the first tested standard treatment for PER using ARIA classification, and shows prompt short-term and long-term relief of symptoms, improves patients' QoL, and provides economic benefits to employers and the society.