This chapter presents a practical case study illustrating step-by-step how to conduct a cost–benefit analysis (CBA) of remediating an industrial site in Mexico. The objective of the chapter is to guide the reader in the construction of a CBA using Excel. The case study described follows the order of the previous chapters. It starts with a description of the industrial site and the interventions available for remediation. The chapter describes how to perform each step of CBA in Excel from “defining the analysis” (Step 1) to “testing the sensitivity of the results” (Step 7). Each section is complemented with an Excel spreadsheet and solution file.