During the COVID-19 pandemic, people voluntarily reduced their necessary healthcare. We examined whether supplying educational digital versatile discs (DVDs) before admission can reduce parental rejection of pediatric cardiac catheterization for congenital heart disease (CHD). Parents of 70 children with CHD selected for cardiac catheterization were randomly allocated to the DVD (received pre-admission DVDs in the outpatient department; 70 parents of 35 children) or non-DVD groups (did not receive the DVDs; 70 parents of 35 children). The parents could reject the admission of their children within 7 days. Cardiac catheterization was rejected by 14 (20.0%) and 26 (37.1%) parents in the DVD and non-DVD groups, respectively (p= 0.025). Parent Perceptions of Uncertainty Scale scores were lower in the DVD (128.3 ± 8.9 points) than in the non-DVD group (134.1 ± 7.3 points;p< 0.001). Decreased uncertainty due to pre-admission DVD watching could have contributed to the increased parental willingness for cardiac catheterization. The effects of pre-admission educational DVDs were more significant among parents with a lower education, rural residence, with only one child, female child, or younger child. Offering educational DVDs to parents of children selected for cardiac catheterization for CHD may decrease the parental rejection rate of the treatment.