In the face of extraordinary advances in the prevention, diagnosis, and treatment of human diseases, the inability of most tissues and organs, to repair and regenerate after damage is a problem that needs to be solved. Stem cell research is being pursued in the hope of achieving major medical breakthroughs.In maxillofacial region the Regeneration & Repair of damaged periodontal tissue, bone, pulp, and dentin are problems that the dentist faces today. Stem cells have potential to regenerate dentin, periodontal ligament, cementum and can be used for bone defect therapy. The proper utilization of stem cells can full fill the quest to live a long and healthy life which is as old as the appearance of the first cell on earth. So this book basically aims at reviewing the stem cells types, sources, clinical implications both in medical and dental field and along with their roll in tissue engineering.