Exosomes are small secretory vesicles that are involved in intercellular communication. Exosomes are secreted by many types of cells and exert important functions in plasma-membrane exchange as well as the transport of bioactive substances, such as proteins, messenger ribonucleic acids (mRNAs), micro ribonucleic acids (miRNAs) and organelles. Exosomes may regulate physiological processes by altering gene regulatory networks or epigenetic recombination. Recent studies have shown that exosomes secreted by stem cells can effectively transport proteins, mRNAs and miRNAs and play important roles in the regulation of tissue regeneration. This report reviews current progress in exosome studies as well as their emerging roles in stem cell research and potential clinical use.