A growing number of recent studies have highlighted bats as a reservoir for Leptospira bacteria, pointing out the potential role of bats in the epidemiology of the most widespread zoonotic disease in the world [1]. Because leptospirosis is a largely neglected disease, a number of unan-swered questions remain about the ecology and evolution of Leptospira, especially those associated with bats. Here we summarize what has been recently learned about this emerging but enigmatic host–pathogen association. We show how this system can provide exciting new opportunities to obtain insights into the evolutionary ecology of bat-borne pathogens and propose future directions to disentangle the role of bats in human leptospirosis. What Do We Know, Briefly, about Leptospirosis and Leptospira?