Cytomics, an ad hoc term, represents a new field which connects cyto- with -omics. The cyto- arises from analytical cytology or cytometry, which has developed for more than three decades and includes a serial of quantitative technology which can separate the heterogenetic cell populations into different cytomes by molecular probes. The -omics comes from proteomics which is determined by genomics. Therefore, cytomics is to separate the cytomes by cytometry technology and identify their proteomes controlled by genome or special genes. Cytomics project consists of two parts of technology, one is separation of cytomes and another is post-sorting analysis. Development of cytomics related technology would help us to understand molecular basis of different cytomes and the transition between them, to gradually grasp the details of genomics, and to know of how to apply them for clinical work. Thus, a new horizon will appear.