This document is the fifth in a series of hazard-specific risk assessment modules, compiled as part of the Words into Action Guidelines on National Disaster Risk Assessment by UNISDR. This section provides a general introduction to the assessment of biological hazards. This section outlines various approaches to assessing the risk of biological hazards, which differ according to the purpose of the assessment. These include strategic risk assessment, rapid risk assessment, and post-event assessment. This document also outlines ways in which risk assessment can inform policymaking for national DRR measures.