This chapter provides detail description of cord blood stem cells. Cord blood stem cells, embryonic stem cell culture, traditional applications, stem cells-treatment potentials, cord blood stem cells treat fatal disease, cord blood collection and storage, adult stem cells, dental pulp stem cells, corneal limbal stem cells, pancreatic stem cells, liver stem cells, muscle stem cells, neuronal stem cells, gene therapy applications with adult stem cells and future of stem cell therapy are described in detail. 32 references are included at the end of the chapter to facilitate further reading.