Stem Cell Research and Tissue Engineering, in present time, have emerged as a legalized and regulated stem cell treatment option globally, but scientifically, their success is unestablished. Novel stem cell-based therapies have evolved as innovative and routine clinical solutions by commercial companies and hospitals across the world. Such rampant spread of stem cell clinics throughout UK, US, Europe and Asia reflect the public encouragement of benefits to incurable diseases. However, ever growing stem cell therapy developments need constant dogwatch and careful policy making by government regulatory bodies for prompt action in case of any untoward public concern. Therefore, researchers and physicians must keep themselves abreast of current knowledge on stem cells, tissue engineering devices in treatment and its safe legal limits. With this aim, stem cell scienctific developments, treatment options and legal scenario are introduced here to beginner or actively inolved scientists and physicians. Introduction to stem cell therapy will provide basic information to beginner researchers and practice physicians on engineered stem cell research concepts and present stem cell therapy federal regulations in different North American, European and Asian countries. FDA, CDC, EU, ICMR government policies in different countries include information on the current legal position, ethical policies, regulatory oversight and relevant laws.