In this study, nasal samples from children with clinical colds were collected to detect common respiratory viruses associated with viral URIs in pediatric patients. PCR techniques were used to identify viruses, a technique more sensitive than other detection or culture methods (6, 7) . Because children may have prolonged shedding with some respiratory viruses, particularly rhinovirus, in the absence of symptoms (21, 22) , we collected specimens on study participants both when they were well and when they were symptomatic. A child was classified as having a viral URI when either a new virus was isolated or a significant increase in viral load of a previously identified virus was detected in the presence of acute symptoms. With these techniques, we identified a virus in 57.4% of children whose parents thought their child was developing a cold and had at least one respiratory symptom.