SUMMARY: BACKGROUND: Contamination of platelets with bacteria is the major microbiological risk of blood transfusion. Screening for bacterial contamination can reduce the frequency of bacterial transmission considerably. In the present paper, the results of 10-year screening in the Netherlands are described. METHODS: All platelet concentrates were cultured with the BacT/Alert culturing system with large volume (7.5 ml) cultures in either an aerobic or an anaerobic bottle. Products were released on a 'negative-to-date' basis. RESULTS: After introduction of the diversion of the first milliliters of collected blood, the number of positive screening cultures decreased significantly from 0.85% to 0.37%. The frequency of transfusion-transmitted bacterial infections by platelet concentrates is currently less than 1 per 2 years in the Netherlands. CONCLUSION: Over a period of 10 years the bacterial screening system for platelet concentrates proved to result in a safe system with respect to microbiological infection as a result of platelet transfusions.