There is a growing body of evidence showing that the anterior cingulate (ACC) and the orbitofrontal (OFC) cortex are both essential for reinforcement-guided decision making. Focusing on functional connectivity approach through coherence, we studied whether communication between the ACC and OFC through neural synchronization is a necessary stage for performing value-based decision making. We used a T-maze task with a differential reward (Large vs. small reward) and cost (long vs. short waiting time) and simultaneously recorded local field potentials (LFP) from the ACC and OFC. Task-dependent synchronization in theta/low beta (4–20 Hz) frequency bands were observed between areas when rats chose the higher over the lower reward. This synchronization was significantly poorer when rats chose lower rewards or passively performed the task. High-gamma (80–100 Hz) synchrony between areas was also observed, however, it was not dependent on the animal's decision. Our results propose that synchronization between the ACC and OFC in the low-frequency range is necessary during value-based decision making.