The potential association of human parvovirus B19 infection with idiopathic thrombocytopenic purpura (ITP) was studied. All 60 adult patients presenting with ITP at the University Hospital Rotterdam - Dijkzigt during a 12-year period (41 with acute ITP, 19 with chronic ITP) were included. Patient files were retrospectively analyzed. Stored serum samples were tested for parvovirus B19-specific IgG and IgM anti-bodies, and for parvovirus B19 DNA. In only one patient (1.7%) was evidence of recent B19 infection found. Parvovirus B19 is not a frequent cause of adult ITP and should be tested for only when there are other indications of possible parvovirus B19 involvement.