When people listen to music, they often move their body in time with the beat. However, people differ widely in their tendency to 'feel a beat'. Why? Here we combined functional magnetic resonance imaging with a timing task that is diagnostic of individual differences in beat perception and compared the brain activity of individuals who readily perceive an implied beat with those who do not. Activation in auditory and motor areas was correlated with individual differences in beat perception, even when participants performed a timing task in which no behavioral differences occurred. The results support two conclusions. First, a bias toward beat perception is mediated by the activation of cortical circuits involved in rhythm production. Second, some individuals more readily engage these cortical beat-based circuits when making timing judgments than do others.