Claiming contribution in courts is currently a complex and uncertain task, which may lead to the unenforceability of the right to claim contribution in antitrust. The Chapter makes several recommendations that could simplify and make contribution more effective in the competition law context. Firstly, it must be clearly stated that antitrust infringers have the right to claim contribution in the context of EU competition law and that such a right does not interfere with the principle of effectiveness thereof. Secondly, rules on contribution should be the same for private and public antitrust enforcement, they should be based on one type of claim in the form of a personal right to claim contribution, available when the damages and Commission’s fine are paid. The criterion for determining internal liability should be based on a limited number of factors. A two-pillar rule based on division according to market shares and relative fault is suggested. Finally the regimes of special joint and several liability should be simplified and liability sharing agreements should be endorsed. Liability sharing agreements are the simplest and the most effective tool for securing the right to contribution.