In four patients, all girls, aged 2, 3.5, 4 and 5 years, transient erythroblastopenia was diagnosed. The children were presented because of acute pallor. The haemoglobin levels were 2.8 to 5.0 mmol/l. After 3 weeks all patients had recovered or were recovering with increasing haemoglobin values. Three of the four patients needed one blood transfusion. In two patients there was evidence of a parvovirus B19 infection. Transient erythroblastopenia is mostly seen in patients aged 1-4 years. Most cases are postinfectious and there is evidence that human parvovirus B19 is responsible for many cases. In the very young child the differential diagnosis from Blackfan-Diamond anaemia may be very difficult.