Hæmovigilance was part of the reform of the French transfusion system. The hæmovigilance network is now operational with approximately 4600 transfusion incidents reported annually. Immediate incidents observed within 8 days after transfusion account for 85 % of the reports. A cause cannot be identified in 41% of these, usually concerning minor clinical incidents with transient fever and /or shivers. An allergic reaction is described in 31% of transfusion reactions. Immunological conflicts account for 18% and bacteria associated transfusion reactions for 6%. The importance of bacteria associated transfusion reactions, the first identified cause of death associated with transfusion is one of the findings of hæmovigilance. Improvement in the hæmovigilance systems aims at obtaining better descriptions of transfusion incidents, standardisation of severity and imputability assessment and definitions of denominators such as the actual number of recipients. Delayed incidents will ultimately provide a true vision of post transfusion immunisation and infection The improvement of hæmovigilance now considered as part of transfusion medicine practice is a continuous process.