The risk ranking exercises related to biological hazards undertaken in fourteen risk assessments of the EFSA/BIOHAZ Panel were reviewed. The aim was to suggest risk ranking tools to be used in future risk assessments and to analyse strengths and weaknesses of different approaches to risk ranking. It was concluded that there is no universal methodology for risk ranking. A conceptual risk ranking framework with nine separate stages is proposed to allow the adoption of the appropriate risk ranking methodology at each stage. Further, nine risk ranking tools developed by other institutions worldwide were described, although none of these could be recommended as the single risk ranking tool for the BIOHAZ Panel. It is recommended that the risk ranking exercise should take a structured approach and be transparently and consistently documented so to be reproducible. The importance of the proper correspondence between the time frame and the requirements of the risk ranking exercise was stressed as well as the interaction between the risk managers and the risk assessors in the definition of the risk ranking purpose and the presentation of the results. Furthermore the development of a risk ranking toolbox based on the proposed framework should be investigated, since such a toolbox would support the construction of consistent and transparent risk ranking models.