The most frequent viruses associated with respiratory infections are human rhinoviruses (HRVs). Although the majority of HRV infections are mild and self-limited, HRV is an important cause of respiratory disease across all age groups. Recent studies using reverse transcriptase polymerase chain reaction to detect HRV genomes have established the importance of HRVs in predisposing to or causing otitis media, sinusitis and exacerbations of asthma, as well as other lower respiratory tract disorders. Among elderly people, infants and immunocompromised hosts HRV infections are often associated with lower respiratory tract morbidity and rarely mortality. How often active viral replication occurs in the middle ear, sinuses or the lower respiratory tract remains to be determined. However, the high incidence of HRV infections and their frequent association with upper and lower respiratory tract complications highlight the need for more effective means of prevention and treatment.