When a sensory cue was repeatedly followed by a behavioral event with fixed delays, pairs of premotor and primary motor neurons showed significant increases of coincident spikes at times a monkey was expecting the event. These results provided evidence that neuronal firing synchrony has predictive power. To elucidate the underlying mechanism, here we argue some nontrivial characteristics of the predictive synchronous firing developed by spike-timing-dependent plasticity in a paradigm similar to classical conditioning. We find that the computationally developed synchrony shows the modulations of temporal precision, which are quite similar to those observed experimentally. Thus, our model suggests that the important characteristics of predictive synchronous firing, which were previously attributed to an animal's higher cognitive function, can emerge from a synaptic-level mechanism. (Contains 7 figures.)