Human metapneumovirus (hMPV) worldwide causes respiratory tract infections with features similar to those of RSV infection. We describe features of hMPV infections in children and compare some of the characteristics with those of RSV infections. From October 2004 to February 2006, 75 patients, 34 hospitalized and 41 outpatients, were diagnosed with hMPV infections by multiplex PCR applied to nasopharyngeal specimens. While hMPV was found rarely in the early phase of the study, a significant increase occurred in the second winter of the study period. Patients with hMPV infections were older than those with RSV infection; clinical characteristics were similar as was the rate of serious disease among hospitalized patients (intensive care treatment: 18% versus 8%). In conclusion, hMPV leads to endemic and epidemic respiratory disease with features similar to those of RSV and should be considered in the differential diagnosis of upper and lower respiratory tract disease.