The broad spectrum of clinical manifestations associated with B19 parvovirus often allows the infection to go unrecognized. We tested for the presence of B19 parvovirus and the specific serological response in serum from hospitalized patients submitted for viral investigations without any specific indications for B19 parvovirus. We diagnosed human parvovirus B19 infection in four paediatric patients showing different clinical manifestations. The patients, aged between 5 and 8 years, were admitted to hospital for: (1) petechial rash; (2) mononucleosis-like syndrome; (3) neurological syndrome; and (4) respiratory disease (in an immunodeficient patient).