To promote and protect the best interests of children involved in biomedical research, paediatricians have to ensure that participating minors and their parents/legal representatives have understood and assented/consented to the research. Therefore guidelines providing child-specific guidance that are compatible with other international guidelines on informed consent are laid down. Special regard is paid to the willingness to participate and the social and cultural background of the patients, the legal conditions of the countries, the capacity of the child to understand and give his/her informed assent, the adequate communication with the child and the parents, the respect of the will of the patient, the understandable written informed consent of legal representatives and to the evaluation of the informed consent/assent process by competent ethics committees.