As described in previous chapters of this book, DNA methylation is involved in numerous biological processes, and modulation of the activity of DNA methyltransferases (DNMTs) is a powerful strategy to modulate, restore, or reduce DNA methylation. In this chapter, we will present examples of inhibitors of DNMTs (DNMTi) and review the fields of applications of DNMTi mainly as therapeutic molecules, for example, in cancers, cardiovascular or neurological diseases, but also as bioengineering tools. Finally, the limits of currently available inhibitors will be discussed and the perspectives to discover improved DNMTi will be presented.