Sometimes competition problems in markets are caused by restrictive rules and regulations. The enforcement of competition rules will often not be very efficient on these markets and will not tackle the root causes of the competition problems. The OECD Competition Assessment Toolkit provides a hands-on tool for a systematic review of new and existing laws and regulations and shows ways to analyse laws, to evaluate and to suggest alternatives. We will introduce the Toolkit, give examples and show the impressive benefits from its application in a number of countries. With the help of experienced experts we will also explain the role of competition assessment in the advocacy efforts of a competition authority and how it can greatly leverage the role of a competition authority vis-à-vis its government, line ministries, regulators etc. Participants will be asked to contribute their experiences and to work on hypothetical case exercises.