The influence of fluency on recognition memory has been widely investigated in the past 30 years. Numerous studies have found that people tend to endorse more old responses to items that are more fluency. Researchers have posited fluency attribution theory, discrepancy-attribution theory, and perceptual fluecy-disfluency theory to explain how fluency could affect recognition memory. However, an integrated theory has not been provided yet. Earlier studies, using old/new test paradigm, revealed that both perceptual and conceptual fluency could influence subjects’ recognition performance (e.g. Jacoby & Whitehouse, 1989). Studies on influence of fluency on recognition applying parallel R/K paradigm have found that fluency selectively influenced familiarity but not recollection, which has been used as strong evidence to support dual-process theory of recognition memory. Rajarm(1993) investigated the influence of fluency on recognition with Jacoby and Whitehouse paradigm using R/K procedure and she found that the increase of fluency only increased K judgment but had no effect of R judgment. Later she presented semantic-related word or semantic-unrelated before the test word to investigated the influence of conceptual fluency on R/K judgment and found that the increase of conceptual fluency also only affected K judgment but not R judgment (Rajaram & Geraci, 2000). However, recent studies using independent R/K paradigm (see Higham & Vokey, 2004) with Jacoby and Whitehouse paradigm found that fluency influenced both familiarity and recollection, which shed doubts on the results of previous researches. Taylor and Henson (2012) found that conceptual fluency could selectively influence recollection but not familiarity under some circumstance. Some studies even found that fluency affected guess, which is implicit memory, but not familiarity or recollection, which are explicit memory. Further studies are still needed to explore the situations under which fluency selectively affects familiarity, under which it could also affects recollection and under which it affects implicit guessing. Most of the existing studies investigated the effect of fluency on item recognition. Studies on the effect of fluency on source or associate recognition has rarely been conducted. A recent study found that increased fluency could also facilitate source memory. More studies are still needed to investigate the mechanism of fluency’s effect on source memory performance. The result of this study suggested that fluency affects familiarity based source memory but not recollection based source memory. Further studies should also be done to investigate whether fluency could facilitate associate memory under some circumstance and the neuro-cognitive mechanism of fluency’s influence on source or associate memory. Recent studies began to investigate influence of aging on the effect of fluency on recognition. It was found that fluency affected the recognition performance of both young and old subjects, which suggested that aging does not affect this effect. It was also found that enhancing the fluency of test items could facilitate the recognition performance of people with mid Alzheimer disease. Further studies are still needed to investigate more population e.g. children, and investigate whether the neuro-cognitive activities associated with fluency and its influence on recognition are different between different age groups or between healthy and amnesic groups.