Summary Infection with human parvovirus (HPV) B19 was diagnosed in persons with hereditary spherocytosis during an outbreak of erythema infectiosum. A 10-year-old boy had an aplastic crisis of the bone marrow and a maculopapular rash. His mother also had an aplastic crisis, fever, rash and a transiently acellular marrow. Another boy had an aplastic crisis, leucopenia and fever, but did not have a rash. Aplastic crisis and a rash have rarely before been observed together and attributed to infection with HPV.