Childhood maltreatment (CM) is all too frequent among western societies, with an estimated prevalence of 10 to 15%. CM associates with increased risk of several psychiatric disorders, and therefore represents a worrying public and socioeconomic burden. While associated clinical outcomes are well characterized, determining by which mechanisms early-life adverse experiences affect mental health over the lifespan is a major challenge. Epigenetic mechanisms, in particular DNA methylation, represent a form of molecular memory that may modify brain function over extended periods of time, as well as serve as a bio-marker of behavioral phenotypes associated with CM. Here, we review human studies suggesting that DNA methylation is a crucial substrate mediating neurobiological consequences of CM throughout life, thereby potentiating maladaptive behavioral patterns and psychopathological risk.