Objectives: The aim of this study was to assess the effectiveness and safety of levocetirizine in the treatment of the symptoms of seasonal allergic rhinitis (SAR) in patients consulting their primary care doctor. Methods: Open-label uncontrolled and non-randomised multi-centre study including patients presenting symptoms of SAR and treated with levocetirizine tablets, 5 mg OD, for 4 weeks. Inclusion criteria: patients with nasal symptoms who were not on treatment or not responsive to treatment, or affected by excessive adverse events due to the antihistamines used previously. There were two visits (initial and after four weeks). Primary end point: efficacy as measured by T4SS (combined score of sneezing, rhinorrhoea, nasal and ocular pruritus, ranging from 0 to 12 recorded by the patient); change in Clinical Global Impression (CGI-c) as rated by the general practitioner, subjective satisfaction with and preference for levocetirizine. Secondary end points: treatment-related adverse events. Results: 1290 patients were evaluated. Before the start of the study, 61.2% did not use any medication, 36.4% took antihistamines which were not effective, and 27.0% of those previously treated patients experienced excessive adverse events. Statistically significant decreases (p < 0.01) compared to baseline were observed for each individual symptom of the itemised T4SS as well as for the global T4SS. The CGI-c improved in 91.1% of the patients who had received treatment previously and 96.8% of those who had not. Of the patients who had received treatment previously, 91.7% (p < 0.01) were satisfied with the study treatment and 84.5% of these patients reported they would prefer levocetirizine in future. All adverse events (somnolence, fatigue, headache, dry mouth) decreased by comparison with previous treatments after levocetirizine was used. Conclusion: Levocetirizine showed an improvement in symptom control for SAR and was preferred by patients compared to the antihistamines they had taken previously. Levocetirizine was well tolerated.