Prophylactic platelet transfusions are considered as standard in most hematology centers, but there is a long-standing controversy as to whether standard prophylactic platelet transfusions are necessary or whether this strategy could be replaced by a therapeutic transfusion strategy. In 106 consecutive cases of patients receiving 140 autologous peripheral blood stem cell transplantations, we used a therapeutic platelet transfusion protocol when patients were in a clinically stable condition. Platelet transfusions were only used when relevant bleeding occurred (more than petechial). Median duration of thrombocytopenia <20 x 10(9)/l and <10 x 10(9)/l was 6 and 3 days, which resulted in a total of 989 and 508 days, respectively. In only 26 out of 140 transplants (19%), we observed clinically relevant bleeding of minor or moderate severity. No severe or life-threatening bleeding was registered. The median and mean number of single donor platelet transfusions was one per transplant (range 0-18). One-third of all transplants, and 47% after high-dose melphalan could be performed without any platelet transfusion. Compared with a historical control group, we could reduce the number of platelet transfusions by one half. This therapeutic platelet transfusion strategy can be performed safely resulting in a considerable reduction in prophylactic platelet transfusions.