Cartel members are jointly and severally liable for damages. This statement raises several questions: Who is jointly and severally liable as addressee of the damages claim stipulated in Section 33 of the German Act against Restraints of Competition? Is there a claim for contribution amongst antitrust defendants? Which criteria are applied in calculating the claim for contribution? How to deal with the statute of limitations for the contribution claim and with settlements between cartel members and cartel victims? Are leniency applicants to be treated differently? The study examines the current question of contribution amongst cartel members based on the legal doctrine of joint and several liability. The evaluation of the objective of cartel damage claims and of contribution claims serves as a starting point. The economic analysis of law, a comparison with US law and the recourse to empirical studies are instrumental in finding answers to the above mentioned questions.