Omics technologies such as proteomics, genomics, and metabolomics are widely applied for the identification and characterization of new molecular signatures. However, molecular profiling that makes it possible to understand neurodegenerative diseases has been relatively insufficient. Brain diseases such as neurodegenerative diseases and emotional disorders need integrative understanding which draws on a more reliable hypothesis for pathology, which can be accomplished via in-depth study of molecular information. Recently, multi-omics technologies have been eagerly applied to a diverse range of diseases. As this includes multiple molecular profiling, metadata, and Big Data processing with informatics and computer science, it is possible to provide new macroscopic and microscopic insights in order to better understand diseases. This Special Issue will introduce recent technological advances in multi-omics and the application of omics technology to brain diseases.