Over 17 and 160 types of chemical modifications have been identified in DNA and RNA,respectively.The interest in understanding the various biological func-tions of DNA and RNA modifications has lead to the cutting-edged fields of epigenomics and epitranscrip-tomics.Developing chemical and biological tools to detect specific modifications in the genome or tran-scriptome has greatly facilitated their study.Here,we review the recent technological advances in this rapidly evolving field.We focus on high-throughput detection methods and biological findings for these modifications,and discuss questions to be addressed as well.We also summarize third-generation sequencing methods,which enable long-read and single-molecule sequencing of DNA and RNA modification.