In order to determine if cytomegalovirus seronegative patients are at risk of infection from fresh frozen plasma we reviewed our experience with 21 seronegative marrow transplant recipients who underwent plasma exchange with unscreened plasma. The mean (+/- SD) number of units of plasma required in the procedure was 47.6 (+/- 19.5). The majority of patients, 17 of 21, were followed for 100 days. No patients had evidence of cytomegaloviral infection. We conclude that fresh frozen plasma is not infectious for cytomegalovirus.