This chapter reviews Cost–Benefit Analysis (CBA) as one of the most commonly applied methods for assessing engineering projects, particularly when a choice is to be made between alternatives. It is often wrongly assumed that a CBA is an objective way of assessing costs and benefits and that the result unequivocally presents the best outcome. CBA is rooted in utilitarian thinking in ethics which argues that moral rightness depends on whether positive consequences are being maximized. CBA – together with its underlying ethical theory – has been abundantly criticized in the philosophy literature. This chapter is not just another voice in this "philosophical choir": not because the critique is not valid, but because it does not necessarily dismiss the CBA altogether. The chapter aims to show what a CBA can and cannot do and how it can be made more suitable for assessing the risks, costs, and benefits of engineering projects. It provides several ways of circumventing some of the ethical objections to a CBA by amending, adjusting, or supplementing it – and when none of these can help – rejecting the CBA as a method and substituting a multi-criteria analysis.