In 1998, the first human embryonic stem (ES) cell was isolated and grown in culture. controversy over the right to harvest and manipulate stem cells, which can potentially be engineered into any cell type in the human body, and may also be genetically altered. Exploration of methods by which human stem cells, both embryonic and adult, may be utilized medicinally to replace diseased cells, prevent the progression of disease, or even prevent disease from occur­ring, has greatly accelerated. In response, the FDA has quickened its efforts to meet scientific discovery in order to assure the safety and clinical benefit of products comprising living cells. The regulation of cells presents exceptional challenges because each cell type is unique, and may not be easily characterized as compared to a traditional pharmaceutical. Although biologics continue to be developed along a similar path as drugs, the FDA is releasing a quickly evolving set of guidances, unique to living cells and even in some cases specific to cell types. In the follow­ing sections, the general “roadmap” by which a biological/cell product can be brought to market is discussed.