Biorepository research in children raises numerous ethical questions that are heightened in the pediatric intensive care unit (PICU) setting. We conducted a cross-sectional, interview-based study of 20 adolescent/young adult (A/YA) PICU patients and 75 parents of PICU patients to elucidate perspectives on biorepository research. A/YAs had a positive attitude toward biobanking. In young adults, comprehension was higher for knowledge of a choice to withdraw and participate in the research and lower for purpose, procedures, risks, and benefits of participation. All but one A/YA wanted to have a say in whether their samples would be used. Parent views on child assent were mixed; 55% of parents favored child involvement in decisions. Efforts should be made to improve comprehension by A/YAs and involvement of A/YAs in decisions.