Stem cell therapy has emerged as a new direction in the field of regenerative medicine. Hundreds of workers throughout the world continue to refine and explore the role of bone marrow and cord blood stem cells for their regular use to solve hematological and immune mediated disorders since many years. Many of them are working to explore the uses of the different types of adult mesenchymal stem cells found in bone marrow and cord blood that could be corrected by replacing cells in the damaged tissues in their own lineages. In recent years stem cell research is being pursued in the hope of achieving major medical breakthroughs. Scientists are striving to create therapies that rebuild or replace damaged cells with tissues grown from stem cells and offer hope to people suffering from cancer, diabetes, cardiovascular disease, spinal-cord injuries, and many other neurodegenerative disorders. Both adult and embryonic stem cells may also provide a route for scientists to develop valuable new methods of drug discovery and testing.