“Omics” are defined as a group of disciplines that aim to collect a large number of biological molecules involved in the function of an organism. In the last decades, technological evolution allowed us to better understand global changes in genes, proteins and metabolites, giving rise to genomics, proteomics, metabolomics, among others. These fields have contributed to the generation of knowledge regarding the cause of diseases. The application of the “omics” to the clinics could help diagnose or prevent certain diseases. In the future, treatment will be specific for each patient according to their genetical background and environment exposure, creating personalized medicine. This article defines every –omic, the technological tools used for its analysis, and examples of its clinical applications.