A growing body of literature shows that imaging contrary-to-truth experiences can change memory. Recent experiments are reviewed to show that when people think about or image a false event, entire false memories can be implanted. Imagination inflation can occur even when there is no overt social pressure, and when hypothetical events are imaged only briefly. Overall, studies of imagination inflation show that imagining a counter-factual event can make subjects more confident that is actually occurred. We discuss possible mechanisms for imagination inflation and find that, with evidence supporting the involvement of both source confusion and familiarity in creating inflation, the primary mechanism is till to be determined. We briefly review evidence on individual differences in susceptibility to inflation. Finally, the widespread use of imagination-based techniques in self-help and clinical contexts suggests that there may be practical implications when imagination is used as a therapeutic tool.