Provided are a method to display a mark-up document according to a parental level, a method and an apparatus for reproducing AV data in an interactive mode, and a data storage medium. The data storage medium includes the AV data, and mark-up documents to reproduce the AV data in an interactive mode. Here, among the mark-up documents, a start-up document contains information on the mark-up documents to be displayed according to a set parental level.