Despite great efforts to improve understanding and treatment of pancreatic cancer, mainly pancreatic ductal adenocarcinoma (PDAC), the outcome of this malignant disease today is still very poor. With the introduction of modern sequencing methods and improvements in computational possibilities, microbiome research is an improving and promising field with a link to many possible diseases. In this article, the results of how the microbiome and PDAC influence each other are reviewed, and future directions are discussed.