Asthma (A) and allergic rhinitis (AR) are common conditions with evidence of shared epidemiological and patho-physiological backgrounds. A systematic review of the literature in the last three decades was performed to summarize both the prevalence and the economic burden of concomitant AR in adult patients with asthma. The reported prevalence estimates of concomitant AR in patients with asthma in the United States and in Europe studies is in excess of 50%, with up to 100% prevalence reported in patients with allergic asthma. In these populations, asthma-related medical resource use, including asthma attacks, emergency room visits, physician visits, and prescription medication use, is higher among asthmatic patients with concomitant AR compared to those without AR. These patients also experience more frequent absence from work and decreased productivity. A low prevalence (6.2%) of comorbid AR in people with asthma has been reported in a single study from Asia. A combined treatment strategy as recommended by international guidelines may improve asthma outcomes in asthmatic patients with concomitant AR.