A probabilistic risk assessment procedure is developed which can predict risks of explosive blast damage to built infrastructure,and when combined with life-cycle cost analysis,the procedure can be used to optimise blastmitigation strategies.The paper focuses on window glazing since this is a load-capacity system which,when subjected to blast loading,has caused significant damage and injury to building occupants.Structural reliability techniques are used to derive blast reliability curves for annealed and toughened glazing subjected to explosive blast for a variety of threat scenarios.The probabilistic analyses include the uncertainties associated with blast modelling,glazing response and glazing failure criteria.Damage risks are calculated for an individual window and for windows in the facade of a multi-storey commercial building.The paper shows an illustrative exampie of how this information,when combined with risk-based decision-making criteria,can be used to optimise blast mitigation strategies.