In the article, the authors refer to the practice of the Court of Arbitration for Sport (CAS) in cases of bringing clubs to disciplinary responsibility for the use of pyrotechnics by fans. Such disputes in the disciplinary practice of UEFA and CAS have features related both to the way the fan commits an offense and to the assessment of the seriousness of the act and respect for the principle of proportionality of the sanction. Resort to the decisions of the Court of Arbitration for Sport helps to get answers to these and some other questions of clubs responsibility for the use of pyrotechnics by fans. With the actual status of CAS in the field of sports law, it means bringing legal certainty to the regulation of the UEFA Disciplinary Regulations.