Background: Long-acting β2 agonists (LABAs) are effective second-line bronchodilator controller agents in asthma, although they may also increase the risk of hospitalization and asthma-related death in certain situations. Despite the interesting findings obtained with short-acting β2 agonists (SABAs), negative studies are available with LABAs in the treatment of allergic rhinitis. This is quite surprising given that there is now clear documentation of the link between asthma and allergic rhinitis. Objective: The aim of this review is to examine the role of β 2 agonists in patients with asthma who also suffer from allergic rhinitis and to try to explain the differences observed between SABAs and LABAs in rhinitis. Methods: SCOPUS, GOOGLE SCHOLAR and MEDLINE were searched for abstracts and papers; the search was completed in March 2008. No restriction was placed on language. Conclusion: The intriguing united airway concept led to the hypothesis that common therapies may influence both and asthma and allergic rhinitis. Consequently, better designed studies with LABAs in allergic rhinitis are now mandatory. In particular, further studies are necessary to investigate clinically relevant anti-inflammatory synergy between inhaled corticosteroids and LABAs in upper airways. It will also be interesting to assess whether ultra-LABAs (once-daily LABAs) are active in allergic rhinitis, although the information we have seems to exclude a role for these agents. © 2008 Informa UK Ltd.