Nowadays, adult stem cells are the main target of biological research. Stem cell specific markers allow the extraction in enough quantity and high purity of multipotent cells from organic tissues, and their usage instead of the ethically reprehensible embryonal stem cells in experimental therapeutic purposes is also possible. The key point in the development of a new, stem-cell based therapeutic methodology is the determination of stem cell specific cell surface or cytoplasmatic antigens that makes reliable stem cell identification possible. Bone marrow derived multipotent stem cells can already be suitably identified, and other, more or less organic tissue-derived stem cell specific markers are also available. The first therapeutic interventions have been already done in diseases such as myocardial infarction or diabetes mellitus, and led to promising results.