Rhinoviruses and coronaviruses cause the majority of common colds and play a part in more serious respiratory illnesses that lead to increased morbidity and mortality. Patients who are infants or elderly, have asthma or chronic obstructive pulmonary disease (COPD), or are immunosuppressed have increased frequency of rhinovirus-related respiratory complications. Newer diagnostic tests such as reverse transcriptase polymerase chain reaction (RT-PCR) have greatly expanded our understanding of the importance of these respiratory viruses. Although there are no currently approved antiviral agents for clinical use, our increased understanding of the virus-host interaction should lead to new intervention strategies.