Ronald van Os received his MSc (1989) form the University of Utrecht, the Netherlands. In 1994, he obtained a PhD from the University of Groningen where he worked on the radiation sensitivity of hematopoietic stem cells. In 1995, he became a postdoc at Harvard Medical School in Boston in the laboratory of Prof. Peter Mauch. He worked on the effects of G-SCF and cytotoxic agents on hematopoietic stem cells as well as on stem cell mobilization. He continued to work on stem cell mobilization in the lab of Prof. Willem Fibbe, at Leiden University Medical Center as of 1998. In 2002, he joined the lab of Prof. Gerald de Haan as a senior scientist at the Department of Cell Biology, University of Groningen Medical Center, where he was appointed assistant professor in 2010. He works on hematopoietic stem cell regulation and mobilization in mice as well as on regulation of self-renewal, aging and ex vivo expansion of hematopoietic stem cells. In 2012, he moved with the group of Prof. De Haan to the European Research Institute for the Biology of Aging at University of Groningen Medical Center. Since 2014, he is appointed as scientific coordinator of the Mouse Clinic for Cancer and Aging at the University Medical Center Groningen and since September 2015 as a staff member of the Central Animal facility in Groningen. He has published 57 items (peer-reviewed papers, book chapters). He has been co-promotor of three PhD students. His main interest is the functioning and regulation of hematopoietic stem cells and salivary gland stem cells. Recently, he focused on (stem cell) aging and the role of DNA damage and diet on aging. Now he focuses on healthy aging of three strains of mice in the Mouse Clinic for Cancer and Aging.