Safety surveillance studies have proven essential in research and development of new biological therapies for bleeding disorders as well as other diseases. Although product safety regarding HIV, hepatitis, and other blood-borne infections is currently excellent, potential new infectious agents require continued vigilant monitoring. Inhibitor development is the most common serious side effect of haemophilia replacement therapy. Several aetiological factors associated with inhibitors have been identified, but their true impact is still largely unknown. Moreover, whether plasma-derived and recombinant factor products differ in their immunogenic profiles is an unresolved issue. Coagulation factor products under development and those currently on the market require uniform, long-term surveillance. The European Haemophilia Safety Surveillance (EUHASS) project was recently established to meet these goals. The pharmaceutical industry and clinicians face common challenges complying with these requirements. In rare diseases like haemophilia, obtaining adequate patient numbers poses a challenge. Another challenge is a lack of methods for assessing disease severity, a surprising deficiency in the era of modern medical and laboratory technology. National and international registries can be used to gather required safety surveillance information. Simultaneously, clinicians benefit from well-organized registry data in their daily practice and harmonize the quality of comprehensive haemophilia care by homogeneous follow-up platforms. Experience with such registries comes, for example, from Europe (PEDNET), the USA (CDC/UDC), the UK (UKHCDO), and Sweden (Malmö). It is important to commit to future pharmacovigilance efforts, aiming at high-quality safety surveillance programmes at both the pharmaceutical research community and clinical levels.