We report the human parvovirus (HPV) infection cases diagnosed in 1984 and 1985 in the virological laboratory of C.N.T.S. Detection of viral antigen and total anti-HPV antibodies was performed by electroimmunodiffusion, and specific IgM by antibody-capture-radioimmunoassay. Seven viraemias were found in 38,730 sera sent for detection of hepatitis A and B markers. Twenty-two observations of aplastic crisis are described, with underlying haemolytic anaemias in 21 cases. HPV infection was serologically proven in 4 cases out of 22 rubeolelike illness, and, in 17 cases out of 17 erythema infectiosum (fifth disease). Four cases of vascular purpura (one of which was Schonlein-Henoch purpura) were studied, and HPV antigen was isolated in 2 cases. An observation of arthropathies in a young adult is described. Finally, 2 spontaneous abortions were simultaneous to an HPV infection. Our study allows us to underline the following points: HPV is the principal (but not exclusive) agent of the aplastic crisis in chronic haemolytic anaemias; these acute erythroblastopenias can reveal an unknown haemolytic anaemia, in particular in hereditary spherocytosis; the polymorphism of the clinical expression of HPV infection is important. Some viraemias are asymptomatic, while others are accompanied by vascular purpura, or atypic erythema; HPV has never been isolated in the fifth disease. Nonetheless bringing out of specific IgM and association of HPV infection linked manifestations in a same patient or in a same family shows its responsibility in the fifth disease; HPV responsibility in spontaneous abortions and fetal malformations remains to be demonstrated.