Introduction: According to the variuos risks of heterologous blood transfusions and the decreasing frequency of blood donation, blood sparing methods are required. The aim of this study was to investigate the influence of microdissection technique introduced in 1994 on the frequency of blood transfusion during extensive oncological operations. Method: In a retrospective analysis, the transfusion rate of the years 1992 and 1993 were compared with the transfusion rate of the years 1995 and 1999. In total, 591 patients operated on a malignant tumour were recorded. Results: A significant reduction of the transfusion rate following introduction microdissection technique has been found. The decreased frequency of blood transfusion based on a decreased intraoperative transfusion rate. In 1992 and 1993, the frequency of blood transfusion was 83%. In 1995 and 1999 blood transfusions were required in only 45% of the patients (p Conclusion: With regard to introduction of the microdissection technique using new coagulation instruments and haemostyptica, a significant reduction of the intraoperative transfusion rate hase been observed. These results will be used as guidelines for preoperative blood supply in our institution.