Objective: The prefrontal cortex (PFC), as part of a cortico-hippocampal-subcortical circuit is mandatory for the achievement of mnemonic and executive tasks. Within the framework of anatomical connections, flexible binding of neuronal populations in oscillatory rhythms underlies such complex abilities. However, the mechanisms governing the maturation of oscillatory activity in the PFC and related network are still unknown. Here, we characterize for the first time oscillatory patterns of activity during postnatal development of the PFC and highlight the developmental interactions within the prefrontal-hippocampal circuit. Methods: For this we performed extracellular and multielectrode recordings in vivo in the PFC and the hippocampus of urethane-anesthetized rat pups from postnatal day P0 to P15. Results: We characterized three distinct patterns of intermittent oscillatory activity in the PFC. (1) Short immature gamma oscillations synchronize the PFC locally around birth. (2) Spindle bursts (SB) with similar properties as in primary sensory cortices appeared as early as P3. (3) Nested gamma spindle bursts (NGS) of 1-3s duration and around 9 Hz in frequency are firstly generated at P5 and represent a unique oscillatory pattern of the neonatal PFC. Spike analysis revealed a strong correlation between NGS and isolated clusters of units. According to current-source density analysis generation of SB mainly involves a network within the superficial anterior cingulate region of the PFC, whereas NGS are confined to the deeper prelimbic/infralimbic area. Starting with P10 the PFC activity becomes continuous with dominant frequency in theta band and nested gamma episodes. Simultaneous recordings from PFC and hippocampus showed a temporal correlation between SB/NGS and the immature hippocampal oscillations. Conclusion: These results reveal the early presence of complex patterns of activity in the developing PFC and a role of hippocampal activity for their generation.