This chapter looks at evidence to support the business case for sustainability. Based on a sustainable business model, the real drivers for corporations becoming more sustainable are sought. The same ‘chicken and egg’ question comes back again and again: are companies more successful because they are run in a sustainable manner or is it that already successful companies are those that apply sustainability successfully too? Is there a new breed of CEOs who are less driven by the short term and who look to the longer term, seeking to build a solid reputation on the basis of a sustainable approach? What are the tools that currently exist to measure the direct and indirect effects of sustainability on the bottom line?