In the twenty-first century the medieval ended up in a place where - only a few decades ago - no one would have expected to find it: the genetics lab. Today, highly specialized state-of-the-art research institutes are busy analysing medieval DNA samples. The objects they scrutinize represent the entire Middle Ages. Sometimes the scientific objective of the analysis resides primarily in the realm of history/archaeology; sometimes the questions asked are of a biological nature. A rapidly growing field of more or less intertwined genetic, historical, and archaeological knowledge production is developing, and the medieval has become relevant to genetics, as well as the other way around. Given the breath-taking pace of research, it is virtually impossible to keep track of all pertinent developments. This paper demonstrates the relevance of the medieval for genetics in several contexts: medieval pandemics constitute a source of important data for today’s medical research; medieval migrations are both showcases and test cases for the tools of population genetics, and the medieval millennium (500-1500 AD) might well become an essential period for studies in recent human evolution. Even such much-studied medieval objects as parchments have the potential to reveal a whole field of previously hidden data by providing polyvalent source material. Yet real interdisciplinary cooperation between geneticists and medievalists remains rare. There is an urgent need for more critical engagement, which should hopefully also provide us with more complete overviews of the growing field of which the present contribution is only intended to give some initial insights.