Previous studies have shown that prefrontal cortex (PFC) plays an important role in working memory and decision-making processes. Specifically, in tasks in which a sample stimulus has to be held in memory during a brief delay and then compared to a subsequent test stimulus (delayed-matching to sample paradigm), neurons in PFC show enhanced spiking activity whenever the sample stimulus matches the test stimulus (Miller et al, 1996). This enhancement could encode the match between the test stimuli with the item held in memory and thus mediate the decision to report a match. We investigated whether the local field potential (LFP) recorded in PFC of rhesus monkeys also carries information about whether the test stimulus matched the sample and whether this signal predicted the behavioral choice. In a delayed matching to sample paradigm a sample stimulus was presented followed by a probe stimulus after a delay period. The task required the animal to initiate a lever response if the two successively presented stimuli were identical (match). In the other case (non-match), the animal was required to withhold the lever response. Consistent with previous findings the majority of PF neurons showed enhanced spiking activity in match-trials (70%, Binomialtest, p<0.02). This effect was also reflected in the simultaneously recorded LFP, at the majority of the recorded sites the visual evoked response to the test stimulus was stronger in match vs. non-match cases (85%, Binomialtest, p<0.001). Furthermore, the magnitude of the evoked response predicted the animal’s behavior: In cases in which the animal correctly reported a match, we observed a significantly larger evoked response than in cases in which the animal missed a match (t-test, t39>4.7, p<0.001). In addition, we found a significant positive correlation between the latency of the evoked response and the reaction time of the animal. The response of the animal did not follow the evoked response at a fixed latency. Rather, an i