Energy management and carbon accounting schemes are increasingly being adopted as a corporate response to climate change. These schemes often demand the setting of ambitious targets for the reduction of corporate greenhouse gas emissions. There is however only limited empirical insight in the companies’ target setting process and the auditing practice of certifying agencies that evaluate ambition levels of greenhouse gas reduction targets. We studied the target setting process of firms participating in the CO2 Performance Ladder. The CO2 Performance Ladder is a new certifiable scheme for energy management and carbon accounting that is used as a tool for green public procurement in the Netherlands. This study aimed at answering the question ‘to what extent does the current target setting process in the CO2 Performance Ladder lead to ambitious CO2 emission reduction goals?’. The research methods were interviews with relevant stakeholders (auditors, companies and consultants), document reviews of the certification scheme, and an analysis of corporate target levels for the reduction of CO2 emissions. The research findings showed that several certification requirements for target setting for the reduction of CO2 emissions were interpreted differently by the various actors and that the conformity checks by the auditors did not include a full assessment of all certification requirements. The research results also indicated that corporate CO2 emission reduction targets were not very ambitious. The analysis of the target setting process revealed that there was a semi-structured bottom-up auditing practice for evaluating the corporate CO2 emission reduction targets, but the final assessment whether target levels were sufficiently ambitious were rather loose. The main conclusion is that the current target setting process in the CO2 Performance Ladder did not necessarily lead to establishing the most ambitious goals for CO2 emission reduction. This process and the tools to assess the ambition level of the CO2 emission reduction targets need further improvement in order to maintain the CO2 Performance Ladder as a valid tool for green public procurement.