Haemovigilance is a tool to improve the quality of the blood transfusion chain, primarily focusing on safety. In this review we discuss the history and present state of this relatively new branch of transfusion medicine as well as some developments that we foresee in the near future. The top 10 results and conclusions are: (1) Haemovigilance systems have shown that blood transfusion is relatively safe compared with the use of medicinal drugs and that at least in Europe blood components have reached a high safety standard. (2) The majority of the serious adverse reactions and events occur in the hospital. (3) The majority of preventable adverse reactions are due to clerical errors. (4) Some adverse reactions such as anaphylactic reactions often are not avoidable and therefore have to be considered as an inherent risk of blood transfusion. (5) Well-functioning haemovigilance systems have not only indicated how safety should be improved, but also documented the success of various measures. (6) The type of organisation of a haemovigilance system is of relative value, and different systems may have the same outcome. (7) International collaboration has been extremely useful. (8) Haemovigilance systems may be used for the vigilance and surveillance of alternatives for allogeneic blood transfusion such as cell savers. (9) Haemovigilance systems and officers may be used to improve the quality of aspects of blood transfusion other than safety, such as appropriate use. (10) Haemovigilance systems will be of benefit also for vigilance and surveillance of the treatment with other human products such as cells, tissues and organs.