The notes of the classification system are to improve the accuracy and consistency of classification by providing useful information on classification numbers and items. Even though, several notes are used in KDC, they are not enough to keep up with rapidly developing and expanding knowledge of nowadays. The purpose of this study is to suggest appropriate types and improvements of the notes in KDC 5th edition. In order to achieve these purposes, transition of notes in KDC was analyzed. Notes of DDC 23rd edition, NDC new 9th edition, and KDC 5th edition were also analyzed. Based upon these comparison and analysis, problem and improvement of notes in KDC were suggested.